Fast-curing polyurethane adhesives derived from environmentally friendly hyperbranched polyglycerols - The effect of macromonomer structure

Transformation of glycerol to hyperbranched polyglycerols (HBPGs) and their further application as macromonomers for fast-curing polyurethane adhesives were described. An approach allowing for using of hyperbranched polyglycerols derived from renewable glycerol in adhesive technology was investigated. Four hyperbranched polyglycerols of different structures and functionalities were synthesized and crosslinked with polymeric methylenediphenyldiisocyanate (pMDI) and hexamethylenediisocyanate (HDI). Macromolecule functionality and functional group distribution were shown to be a critical factor in terms of the adhesive performance. The studied approach allowed to conclude that environmentally friendly polyglycerols - derived from renewable glycerol - when properly designed could successfully replace petroleum-based ones.     

On Digital Realizations of Non-integer Order Filters

Typical approach to non-integer order filtering consists of analogue design and implementation. Digital realization of non-integer order systems is susceptible to problems such as infinite memory requirement and sensitivity to numerical errors. The aim of this paper is to present two efficient methods for digital realization of non-integer order filters: discrete time-domain Oustaloup approximation and Laguerre impulse response approximation. Properties of both methods are investigated with use of non-integer low-pass filter. Filters realized with presented methods are then used for filtering of EEG signal. Paper concludes with discussion of merits and flaws of both methods.     

Seeds recovered from by-products of selected fruit processing as a rich source of tocochromanols: RP-HPLC/FLD and RP-UPLC-ESI/MSn study

Tocochromanol composition was analysed in the seeds of nine various fruits: apple (Malus domestica Borkh.), red currant (Ribes rubrum L.), gooseberry (Ribes uva-crispa L.), grape (Vitis vinifera L.), pomegranate (Punica granatum L.), Japanese quince (Chaenomeles japonica (Thunb.) Lindl. ex Spach), sea buckthorn (Hippophae rhamnoides L.), watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) and canary melon (Cucumis melo L.), recovered from by-products of fruit industry. The concentration range of subsequent tocopherols (Ts) and tocotrienols (T3s) was as follows: 1.29–29.30, 0.00–11.68, 0.42–95.11, 0.00–7.66, 0.03–5.03, 0.00–0.18 and 0.00–6.68 mg/100 g of seed dry weight for α-T, β-T, γ-T, δ-T, α-T3, β-T3 and γ-T3, respectively. The δ-T3 was not detected in any of the tested seeds. All tocochromanols were successfully separated by rapid RP-HPLC/FLD method and confirmed by the RP-UPLC-ESI/MS³ technique.     

Partial characterization of a new kind of Chilean Murtilla-like berries

The aim of this research was to characterize a new kind of Chilean Murtilla-like berries (Myrteola nummularia (Poiret) Berg. Myrtaceae, called by locals as Daudapo) vs.well known Murtilla, blueberries, raspberries and black chokeberries. Polyphenols, flavonoids, flavanols and tannins and the level of antioxidant activity by ABTS, FRAP and CUPRAC radical scavenging assays of methanol extract of studied berry samples were determined and compared. It was found that the contents of the polyphenol compounds and the level of antioxidant activity in extracts of berries differ significantly (P < 0.05). The significantly highest contents of polyphenol compounds were in methanol extract of non-ripe Murtilla (121.31 ± 5.9 mg GAE/g for polyphenols; 14.43 ± 0.7, 31.79 ± 1.5, and 9.93 ± 0.3 mg CE/g for flavonoids, tannins and flavanols, respectively). Also the antioxidant activity according to ABTS, FRAP and CUPRAC was significantly highest in methanol extract for non-ripe Murtilla (878.18 ± 41.2, 486.92 ± 23.3 and 1012.42 ± 43.2 ??M TE/g, respectively). The amount of polyphenol compounds and their antioxidant activities of Murtilla berries are significantly higher than in other studied berries and are comparable with blueberries and raspberries, however, these indices in the Murtilla-like non-ripe berries were the following: 31.55 ± 1.4 mg GAE/g for polyphenols; 5.22 ± 0.3, 12.16 ± 0.6 and 2.24 ± 0.1 mg CE/g for flavonoids, tannins and flavanols; ABTS, FRAP and CUPRAC: 244.22 ± 12.1, 81.32 ± 3.9 and 203.83 ± 9.3 ??M TE/g, respectively. The correlation between the polyphenol compounds and the antioxidant activities were relatively high. DPPH kinetic measurements were used to compare, distinguish and discriminate the antiradical activity among berry methanolic extracts by multivariate analysis. 3-D fluorescence was used as an additional tool for the characterization of the polyphenol extracts during various stages of ripening and different berries cultivars. The interaction between methanol polyphenol extracts of Murtilla-like and bovine serum albumin (BSA) showed that the new kind of berries has a strong ability, as other studied berries, to quench the intrinsic fluorescence of BSA by forming complexes.In conclusion, for the first time these berries were analyzed and compared with widely consumed cultivars, using their polyphenols' composition, antioxidant activities and fluorescence properties. The ability of Murtilla-like berries to quench the intrinsic fluorescence of BSA and relatively high content of polyphenol compounds can be used as a new source of antioxidants.     

Application of ZnO single crystals for light-induced water splitting under UV irradiation

This paper presents experimental results of implementation of ZnO single crystals as photoanodes in photoelectrochemical (PEC) cells for hydrogen generation through the process of water splitting. Both, as-grown and O₂-annealed ZnO single crystals were investigated for this purpose. A 351 nm argon laser line was used as the light source. The XRD investigations showed that used ZnO crystals are of good crystalline quality. It was found that the as-grown ZnO single crystals possess higher conversion efficiencies comparing to the O₂-annealed one. The photocurrent density was found to increase significantly with the increase of external bias applied and excitation light intensity. Time dependent photocurrent density characteristics showed that the decay of photocurrent density was not observed within the measurement time. The differences in behaviour of the as-grown and the annealed in O₂ ZnO single crystals are discussed in terms of crystals intrinsic defects.     

DNS‐Class: immediate classification of IP flows using DNS

Nowadays we see a tremendous growth of the Internet, especially in terms of the amont of data being transmitted and new network protocols being introduced. This poses a challenge for network administrators, who need adequate tools for network management. Recent findings show that DNS can contribute valuable information on IP flows and improve traffic visibility in a computer network. In this paper, we apply these findings on DNS to propose a novel traffic classification algorithm with interesting features. We experimentally show that the information carried in domain names and port numbers is sufficient for immediate classification of a highly significant portion of the traffic. We present DNS‐Class: an innovative, fast and reliable flow‐based traffic classification algorithm, which on average yields 99.8% of true positives and < 0.1% of false positives on real traffic traces. The algorithm can work as a major element of a modular system in a cascade architecture. Additionally, we provide an analysis on how various network protocols depend on DNS in terms of flows, packets and bytes. We release the complete source code implementing the presented system as open source. Copyright © 2014 John Wiley & Sons, Ltd.     

Expression, purification and kinetic properties of human recombinant phospholipase C delta 3

Fucosylated histo-blood group antigens such as Lewis b, Lewis Y, and H accumulate in colon carcinoma and this is accompanied by a clear increase in alpha(1-2)fucosyltransferase activity, a key enzyme for the biosynthesis of these antigens. Yet the biological significance of alpha(1-2) fucosylated structures is not well defined. We have transfected a poorly tumorigenic rat colon carcinoma cell line with the human H blood group alpha(1-2)fucosyltransferase cDNA. This resulted in cell surface expression of H antigens with a concomitant decrease of sialic acid substituted and free beta-galactosides. Immunoprecipitation experiments showed that H antigens were essentially borne by variants of CD44 carrying amino acid sequences encoded by exon v6. The transfected cells showed increased motility in a wound healing assay, without changing their proliferation rates. Parental and control cells transfected with an empty vector formed small tumors that always regressed after 30 days when injected subcutaneously to syngeneic rats. In contrast, alpha(1-2)fucosyltransferase transfectants were able to form progressive tumors. Increased tumorigenicity was also visible in nude mice. These results demonstrate that alpha(1-2)fucosylated antigens contribute directly to aggressiveness of colon carcinoma cells. This could occur by altering a function of CD44 variants.     

High-temperature electrical transport properties of buckypapers composed of doped single-walled carbon nanotubes

Data on temperature-dependent electrical resistance of buckypaper flakes are presented in this paper. The buckypapers are composed of ropes of aligned single-walled carbon nanotubes doped with HNO₃, which are treated as mixed systems with their properties being dependent on the treatment performed. The measurements cover rather wide temperature range from 300 up to 900 K. In case of untreated samples, curves with two well-defined activation energies are seen, which are discussed in terms of different DC conductivity mechanisms, with a great attention paid to the parallel metal-semiconductor system. In turn, in heat-treated samples the resistance is found nearly temperature-independent except for the significant peak centered at about 600-650 K. Observed characteristics are also fitted using the parallel model, although with a less accuracy suggesting influence of another conductivity mechanisms. At any rate, the resistance peak is possibly related to the metal/non-metal transition observed in disordered solids.