Preparation and characterisation of a new double-sided bio-artificial material prepared by casting of poly(vinyl alcohol) on collagen

A new double-sided bio-artificial polymer material prepared by casting of poly(vinyl alcohol) (PVA) on collagen (COLL) was obtained. The single components were blended with lactic acid and glutaraldehyde as plasticiser and crosslinker agents, respectively, to change and characterise structure of both the polymers. Differential scanning calorimetry, dynamic mechanical analysis, tensile test, tear resistance test, scratch test and Fourier transform infrared spectroscopy were chosen to characterise all the prepared materials. The results showed that the additives led to the decrease of glass transition temperature, melting temperature and crystallinity with respect to raw materials. The new bio-artificial material revealed tough behaviour with yield stress, with less by half tensile strength compared to neat materials and with the strain of PVA (>100 %). Both PVA and COLL blends and the new bio-artificial material exhibited viscoelastic features useful for being used in contact with living organism.     

Fischer aminocarbene complexes of chromium and iron: Anomalous electrochemical reduction of p-carbonyl substituted derivatives

This contribution shows how a small change of a remote substituent (COOCH₃ for e.g. OCH₃) on Fischer aminocarbene complexes can change totally the LUMO location, and thus electron distribution, extent of π-electron delocalization and, consequently, redox properties of these potential catalysts. During investigation of redox properties of extended series of title compounds, an exceptionally positive reduction potential was observed (non fitting the LFER plot) for p-COOR substituents. This effect is caused by a strong intramolecular electronic interaction, which is specific for p-phenylene dicarbonyl compounds. In this context, the CN bond in aminocarbene moiety has a double bond character and resembles carbonyl function. The interpretation was proved by DFT calculations.     

SEM–EDX and XRD characterization of zeolite NaA, synthesized from rice husk and aluminium scrap by different procedures for preparation of the initial hydrogel

A number of investigations have demonstrated that zeolite NaA could be synthesized using Si, extracted from rice husk ash; however, experiments on direct extraction of Si from rice husk (RH) are scarce. The main objective of the present study was to explore the possibility to synthesize high-quality zeolite NaA from RH and waste aluminium cans (as a source of Al), applying different procedures for the preparation of initial hydrogel and a unified procedure for crystallization of zeolite NaA. Products were characterized by SEM–EDX and XRD analyses. The investigation demonstrated that Si could be extracted directly from RH, avoiding the process of RH burning. Practically complete dissolution of Si from RH was achieved by alkali treatment (with 10 % NaOH for 7 h) at boiling temperature and atmospheric pressure, i.e. using refluxing system instead of autoclave for the preparation of Si-gel. Zeolite NaA samples synthesized from such Si-gels were pure, highly crystalline and white. Furthermore, it was found that the direct dissolution of Al in Si-gel did not affect the quality of the final product. Although this investigation was not focused on the mechanism of zeolite NaA crystallization, the results obtained indicated clearly that the history of Si-gel preparation played an important role in the nucleation and growth of zeolite NaA crystals and influenced their yield, size, and shape. Therefore, the optimization of Si-gel preparation procedure has to be considered as essential not only for the economy of the synthesis of NaA from RH, but also for the quality of the final product.     

Project management in the nanotechnology industry: Specifics and possibilities of taking them into account

The characteristics of projects in the nanotechnology industry are considered from the viewpoint of resource provision and conditions of realization, and the specifics of project management problems in the nanotechnology industry are shown. The advantages and disadvantages of the most widespread project management methods are shown, and the possibilities of their application to project management problems in the subject area are evaluated. A project simulation approach based on the use of temporal logic tools is proposed. The advisability of developing branching point-interval time methods for the simulation of nanotechnology projects is substantiated.     

www.rnaworkbench.com: A new program for analyzing RNA interference

RNA interference (RNAi) has become an important tool to study and utilize gene silencing by introducing short interfering RNA (siRNA). In order to predict the most efficient siRNAs, a new software tool, RNA Workbench (RNAWB), has been designed and is freely available (after registration) on http://www.rnaworkbench.com. In addition to the standard selection rules, RNAWB includes the possibility of statistical analyses of the applied selection rules (criteria). The role of RNA secondary structures in the RNA interference process as well as the application of sequence rules are discussed to show the applicability of the software.     

The Role of Filippi’s Glands in the Silk Moths Cocoon Construction

Filippi’s glands (FGs), formerly also called Lyonet’s glands, are accessory secretory structures of the labial (silk) glands of lepidopteran caterpillars, which were implicated to play an important role in the maturation of the silk material and the construction of the cocoon. In our previous study, we have identified several species of giant silk moths that completely lack the FGs. Interestingly, the absence of FGs in these species correlates with the construction of a loose cocoon architecture. We investigated the functions of FGs by their surgical extirpation in the last instar larvae of the silkworm, Bombyx mori. We found that the absence of FGs altered the structure of the resulting cocoon, in which the different layers of silk were separated. In further experiments, we found no effects of the absence of FGs on larval cocoon formation behavior or on changes in cocoon mass or lipid content. Differential proteomic analysis revealed no significant contribution of structural proteins from FGs to silk cocoon material, but we identified several low abundance proteins that may play a role in posttranslational modifications of some silk proteins. Proteomic analysis also revealed a difference in phosphorylation of the N-terminal sequence of fibroin-heavy chain molecule. Thus, FGs appear to affect silk stickiness during spinning by regulating posttranslational modifications. This could also explain the link that exists between the absence of these glands and the formation of loose cocoons in some giant silk moth species.     

Nitric oxide(NO) decomposition on catalysts,containing oxides of lanthanum and cerium,supported on γ-alumina

The present work was devoted to study the catalytic activity of lanthanum and cerium oxides separately,deposited on g-alumina in the reaction of decomposition of nitric oxide. The catalyst samples were prepared by the method of impregnation of g-Al_2 O_3 using solutions, containing nitrates of lanthanum and cerium. The prepared samples were calcined for 4 h at temperature 650℃ in an oven in air atmosphere. The catalysts were characterized by: chemical analysis by inductively coupled plasma atomic emission spectrometry(ICP-AES), X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS),scanning electron microscopy(SEM) combined with energy-dispersive X-ray spectroscopy(EDS), electron paramagnetic resonance(EPR) and infrared(IR) spectroscopy, as well as measurement of the specific surface area. The results show that the catalysts based on lanthanum oxide and cerium oxide deposited on alumina display high catalytic activity over 60% conversion degree with respect to decomposition of nitric oxide in the absence of reducing agent. In the presence of reducer the activity reaches 90% conversion degree.     

Inhibition of return to social signals of fear.

The present study examined whether inhibition of return (IOR) is modulated by the fear relevance of the cue. Experiment 1 found similar magnitude of IOR was produced by neutral and fear faces and luminance matched cues. To allow a more sensitive measure of endogenously directed attention, Experiment 2 removed a central reorienting cue and more precisely measured the time course of IOR. At stimulus onset asynchronies (SOAs) of 500, 1,000 and 1,500 ms, fear face and luminance matched cues resulted in similar IOR. These findings suggest that IOR is triggered by event onsets and disregards event value. Views of IOR as an adaptive "foraging facilitator," whereby attention is guided to promote optimal sampling of important environmental events, are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Special state standard for the unit of radionuclide activity in gases

Conclusions As a result of the investigations of the standard of the unit of radionuclide activity in gases carried out by the All-Union Scientific Research Institute for Physical and Radio Engineering Measurements, it follows that the standard of the unit of radionuclide activity in gases ensures the reproduction of the activity unit with an error of l–2% in the activity range 10–20×10⁴ dis/sec·m³.With the help of working standards using gaseous radioactive sources, the transfer of the size of the activity unit to test measuring instruments is ensured, and from these to working measuring instruments through a planned verification scheme.Translated from Izmeritel'naya Tekhnika, No. 11, pp. 8–10, November, 1971.