Macromonomers by activated polymerization of oxiranes. Synthesis and polymerization

Macromonomers were obtained by cationic polymerization of propylene oxide and epichlorohydrin proceeding by the activated monomer mechanism with hydroxyethyl acrylate as initiator. Up to DP _n ～ 15 for propylene oxide and DP _n ～ 20 for epichlorohydrin, polymerization proceeds as a living process, giving with quantitative yields macromonomers with functionality equal to one, controlled molecular weight and narrow molecular weight distribution (M _wM _n<1.2) free of side products. In the higer molecular weight region, side reactions become increasingly noticeable. Propylene oxide macromonomers undergo radical homopolymerization. Homopolymerization of macromonomer with M _n = 8×10² gives graft copolymers with M _n up to 7.2×10³ in copolymerization with styrene, completely soluble graft copolymers with M _n ～ 2×10⁴ were obtained. Radical copolymerization of epichlorohydrin macromonomers with styrene gives initially soluble products with M _n ～ 6×10⁴ were obtained. Radical copolymerization of epichlorohydrin macromonomers with styrene gives initially soluble products with M_n～ 6×10⁴, which are converted in the later stages into insoluble gels, apparently due to the chain transfer to chloromethly groups of the polyepichlorohydrin chains.     

Facile determination of foamability index of non-ionic and cationic frothers and its effect on flotation of quartz

ABSTRACT

In this work, a facile method for determination of foaming properties of frothers was used. It was based on measuring the foam height in a flotation machine at different concentrations of frothers. Based on the foam height-concentration curve, a new foaming parameter, so-called concentration at half of the maximum foam height CMH, was proposed. Assessment and usefulness of CMH were shown in flotation of quartz. The concentration of amine at the critical contact angle CCA, at which amine starts to be a collector, was also determined. The determined values of CCA were similar to CMH and were equal to 1.3, 0.14 and 0.03 mM for ButNH₂, HexNH₂ and OctNH₂, respectively. The values of CMH and CCA depended on the alkyl chain of frothers.     

New business client acquisition using social networking sites

The rapid development and expansion of the social services and social networking sites (SNSs) on the Internet has boosted interdisciplinary research on online communities as a part of social network analysis. Social networking creates a unique opportunity to establish new business contacts with people from unexplored markets to gain new customers or contractors. The goal of the paper is to present a new idea for acquisition of new customers in the business-to-business market using individual human relationships existing SNSs. In order to find an appropriate solution, the SCAN method (System for Client Acquisition via Social Network) has been proposed. This method is a B2B application to support new markets gaining process. It makes use of paths over human relationships that lead in the shortest and steadfast way from the searching company members to the potential clients represented by their selected employees.     

Relational large scale multi-label classification method for video categorization

The problem of automated video categorization in large datasets is considered in the paper. A new Iterative Multi-label Propagation (IMP) algorithm for relational learning in multi-label data is proposed. Based on the information of the already categorized videos and their relations to other videos, the system assigns suitable categories—multiple labels to the unknown videos. The MapReduce approach to the IMP algorithm described in the paper enables processing of large datasets in parallel computing. The experiments carried out on 5-million videos dataset revealed the good efficiency of the multi-label classification for videos categorization. They have additionally shown that classification of all unknown videos required only several parallel iterations.     

A framework for interactive image color editing

We propose a new method for interactive image color replacement that creates smooth and naturally looking results with minimal user interaction. Our system expects as input a source image and rawly scribbled target color values and generates high quality results in interactive rates. To achieve this goal we introduce an algorithm that preserves pairwise distances of the signatures in the original image and simultaneously maps the color to the user defined target values. We propose efficient sub-sampling in order to reduce the computational load and adapt semi-supervised locally linear embedding to optimize the constraints in one objective function. We show the application of the algorithm on typical photographs and compare the results to other color replacement methods.     

Electrochemical and spectral properties of meta-linked 1,3,5-tris(aryl)benzenes and 2,4,6-tris(aryl)-1-phenoles, and their polymers

We present electrochemical and spectral properties of symmetric monomers 1,3,5-tris(aryl)benzenes and 2,4,6-tris(aryl)-1-phenols and their polymers. These compounds contain thienyl, furyl or EDOT moieties attached to central benzene or phenol ring at the meta-position, synthesized by a Stille cross-coupling procedure. All monomers are electroactive and undergo electropolymerization creating thin films on an electrode surface. Polymers with meta-linkages were obtained by electrochemical oxidation. Detailed cyclic voltammetry and in situ UV-vis spectroelectrochemistry show that polymers with hydroxy groups exhibit higher conductivity and better stability than with benzene core. Interesting and different behavior occurs for 2,4,6-tris(2-thienyl)-1-phenol, for which the characteristic, sharp, redox peak is observed.     

Prognostic Role of Tumoral PD-L1 and IDO1 Expression,and Intratumoral CD8+ and FoxP3+ Lymphocyte Infiltrates in 132 Primary Cutaneous Merkel Cell Carcinomas

The association of immune markers and clinicopathologic features and patient outcome has not been extensively studied in Merkel cell carcinoma (MCC). We correlated tumoral PD-L1 and IDO1 expression, and intratumoral CD8+ and FoxP3+ lymphocytes count with clinicopathologic variables, Merkel cell polyomavirus (MCPyV) status, and patient outcomes in a series of 132 MCC. By univariate analyses, tumoral PD-L1 expression >1% and combined tumoral PD-L1 >1% and high intratumoral FoxP3+ lymphocyte count correlated with improved overall survival (OS) (p = 0.016, 0.0072), MCC-specific survival (MSS) (p = 0.019, 0.017), and progression-free survival (PFS) (p = 0.043, 0.004, respectively). High intratumoral CD8+ and FoxP3+ lymphocyte count correlated with longer MSS (p = 0.036) and improved PFS (p = 0.047), respectively. Ulceration correlated with worse OS and worse MSS. Age, male gender, and higher stage (3 and 4) significantly correlated with worse survival. MCPyV positivity correlated with immune response. By multivariate analyses, only ulceration and age remained as independent predictors of worse OS; gender and stage remained for shorter PFS. Tumoral PD-L1 expression and increased density of intratumoral CD8+ lymphocytes and FoxP+ lymphocytes may represent favorable prognosticators in a subset of MCCs. Tumoral PD-L1 expression correlated with intratumoral CD8+ and FoxP3+ lymphocytes, which is supportive of an adaptive immune response.     

Modeling a Murex cabritii sea shell with a structured implicit surface modeler

BlobTree , and its application to the generation of a complex and visually accurate biological model of the sea shell Murex cabritii. Since the model is purely procedurally defined and does not rely on polygon mesh operations, it is resolution independent and can be rendered directly using ray tracing. An interface has been built for the BlobTree using an interpreted programming language (Python). The language interface readily allows a user to procedurally describe the shell based on numeric data taken from the actual object. Published online: 15 March 2002     

Biogenic amines in striatum of rats that had been treated with ethanol, and their brains later stored in different temperatures

The purpose of this study was to investigate how ethanol pretreatment and storage temperatures of brain striatum affect levels of biogenic amines in this tissue. Adult Wistar male rats were injected with 25% ethanol (5.0 g/kg i.p.) while the control rats were administered i.p. with the same volume of saline. Two hours later the rats were decapitated, their brains removed, and the striatum separated. Each striatum was divided into three parts: one part was immediately frozen on dry ice and kept at -70 degrees C; a second fragment was kept in a household refrigerator (+4 degrees C); and the third fragment was kept at +22 degrees C. Twenty-four hours later, levels of DA, DOPAC, HVA, 3-MT, 5-HT, and 5-HIAA in the striatum were assayed by HPLC/ED. Immediately after decapitation; ethanol levels were assayed in the serum of ethanol-pretreated and saline-pretreated rats using gas chromatography. Our results indicate that levels of striatal DA, DOPAC, and HVA in saline-pretreated rats decreased significantly when the storage temperature of the striatum was raised from -70 degrees C, through +4 degrees C, to +22 degrees C, while levels of striatal 5-HT and 5-HIAA remained constant within the temperature range tested and levels of 3-MT fluctuated. In ethanol-pretreated rats, striatal levels of DOPAC, HVA, and 5-HIAA were increased in all three storage temperatures, while levels of DA, 5-HT, and 3-MT were decreased in those temperatures. Those decreases were most profound in striatal samples kept at +22 degrees C. We conclude that concern about possible interactions between drugs and biogenic amines should be exercised.