Compatibilization of kraft lignin‐polyethylene composites using unreactive compatibilizers

This article presents a novel approach to compatibilize Kraft lignin with polyethylene that involves the use of modified poly (styrene‐co‐ethylene‐co‐butylene‐co‐styrene) (SEBS) as unreactive compatibilizers. As SEBS shows no compatibilizing effect on Kraft lignin‐polyethylene composites, SEBS was functionalized via nitration followed by amination to obtain nitrated (SEBS‐NO₂) and aminated (SEBS‐NH₂) SEBS. The compatibilizing effects of SEBS derivatives were studied by means of morphological and mechanical analyses. The results show that SEBS‐NO₂ is less effective than SEBS‐NH₂, the later displaying comparable compatibilizing efficiency to a commercial reactive compatibilizer based on maleated polyethylene. Overall, compatibilization was found to decrease lignin particle size. Addition of SEBS‐NH₂ varying between 1% and 10% improved the tensile strength of composites by up to 96%, elongation at break by up to 64%, and impact strength by up to 48%. Finally, the crystallinity and density of the resulting composites were also studied. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41040.     

Characterization of oligomers from 1,4-butanediol and toluene diisocyanate

Polyurethane oligomers from 1,4-butanediol (BD) and toluene diisocyanate (TDI) with a various excess of BD were synthesized. Their molar masses were measured by gel permeation chromatography and the molar mass distribution correlated with the statistic theory. ¹H-, ¹³C-, ¹H–¹H-COSY–, ATP–, and ¹⁵N-NMR spectra of reaction products were recorded, and from the ratio of proton integrals of characteristic terminal and inner urethane groups, the reactivity ratio of the para and ortho NCO groups in 2,4-TDI was calculated to be approximately 1.8 at a lower excess of BD. ¹⁵N-NMR spectroscopy was found not to be selective enough to detect small amounts of side reactions. © 1993 John Wiley & Sons, Inc.     

Canal wall thickness after preparation with NiTi rotary files

Root canal preparation is the most important phase of endodontic procedure and it consists of adequate canal space cleaning and shaping. In recent years, rotary instruments and techniques have gained importance because of the great efficacy, speed, and safety of the preparation procedure. AIM: The aim of this research was to investigate measurement of maximal and minimal residual dentine thickness (RDT) and canal diameter after the canal preparation with different NiTi rotary files. METHODS: The research has been conducted on extracted human teeth in vitro conditions. The teeth have been divided in seven groups (20 teeth per group) depending on the kind of instruments used for root canal preparation: ProTaper, GT, ProFile, K‐3, FlexMaster, hand ProTaper, and hand GT. The canals have been shaped in a crown‐down manner and irrigated with 5.25% sodium hypochlorite. The roots of the teeth have been cut 1 and 3 mm from the apex. Apical preparation quality has been assessed under the polarized light microscope. RESULTS: The maximal residual dentine thickness at distance 1 mm from apex, ranged from 1.16 to 1.45 mm, and at distance 3 mm from apex, from 1.44 to 1.84 mm. The minimal dentine thickness at distance 1 mm from apex ranged from 0.52 to 0.73 mm, and at distance 3 mm from apex, from 0.66 to 0.83 mm. The canal diameters after preparation at distance 1 mm from apex ranged from 0.42 to 0.49 mm, and at distance 3 mm from apex, from 0.53 to 0.63 mm. CONCLUSIONS: There was no significant difference neither in maximal and minimal RDT, nor in canal diameters shaped with different NiTi instruments tested. All tested NiTi files have accomplished good quality preparation of apical root canal parts. Microsc. Res. Tech., 2011. © 2011 Wiley Periodicals, Inc.     

An integrated approach to optimise parameter design of multi-response processes based on Taguchi method and artificial intelligence

The Taguchi robust parameter design has been widely used over the past decade to solve many single-response process parameter designs. However, the Taguchi method is unable to deal with multi-response problems that are of main interest today, owing to increasing complexity of manufacturing processes and products. Several recent studies have been conducted in order to solve this problem. But, they did not effectively treat situations where responses are correlated and situations in which control factors have continuous values. This study proposed an integrated model for experimental design of processes with multiple correlated responses, composed of three stages which (1) use expert system, designed for selecting an inner and an outer orthogonal array, to design an actual experiment, (2) use Taguchi’s quality loss function to present relative significance of responses, and multivariate statistical methods to uncorrelate and synthesise responses into a single performance measure, (3) use neural networks to construct the response function model and genetic algorithms to optimise parameter design. The effectiveness of the proposed model is illustrated with three examples. Results of analysis showed that the proposed approach could yield a better solution in terms of the optimal parameters setting that results in a higher process performance measure than the traditional experimental design.     

COMPLEMENTARITY OF THE LIVING SYSTEMS AND THE DIALECTICAL SYSTEMS THEORIES: THE CASE OF PUBLIC MEDICAL CARE IN SLOVENIA

Systems science is about synthesis and integration for holism. The living systems (LST) and the dialectical systems theories (DST) are equally old. If both a quite holistic insight and creativity are needed, a combination of the LST and the DST is a better choice than using each of them separately. LST can make many details visible, while DST can make them an information basis for an innovative action. LST alone can hardly provide an action, especially one of a creative orientation. DTS alone can hardly provide all the necessary insight, but it can provide a bridge between different aspects of the process at stake and help them produce creative synergies of different professions' insights. A case of combining both LST and DST in studying public health care proves fruitful. DTS can influence people to use LST and its insight in a creative way.     

Study of curing of epoxy resins by acid anhydrides using differential scanning calorimetry

Course and kinetics of the curing of epoxy resins by acid anhydrides were studied by differential scanning calorimetry (DSC). The heat of reaction at 107.5°C was found to lie between ?302.2to ?333.2 J/g (?72.2 to ?79.6 cal/g), depending on the composition of the reaction system. For one reaction system measurements were made at three different temperatures. From DSC data the reaction order and rate constants were evaluated. Between 18 to 80% conversion the curing reaction was found to be 0.5 order, and from 80 to 98% conversion to be first order. From the rate constants using the Arrhenius equation the activation energy was calculated. The values of the activation energy are 58.2 KJ/mol (13.9 kcal/mol) for 0.5 order and 56.1 KJ/mol (13.4 kcal/mol) for first order reaction.     

Analysis of the urine proteome in patients with pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) accounts for over 213?000 deaths worldwide each year, largely due to late diagnosis. One of the risk factors for the development of PDAC is chronic pancreatitis (CP); the intense desmoplastic reaction makes differentiation between the two conditions extremely difficult. In order to identify biomarkers for noninvasive diagnosis, we performed 2-D DIGE analysis of urine samples from healthy individuals and patients with PDAC and CP. Despite considerable intersample heterogeneity, a total of 127 statistically valid (p<0.05), differentially expressed protein spots were detected, 101 of which were identified using MALDI-TOF MS. A number of these, including annexin A2, gelsolin and CD59 have already been associated with PDAC, however, their validation using immunoblotting proved challenging. This is probably due to extensive PTMs and processing thus indicating the need for raising specific antibodies for urinary proteins. Despite this, our study clearly demonstrates that urine is a valid source of noninvasive biomarkers in patients with pancreatic diseases.     

Structure prediction of the EcoRV DNA methyltransferase based on mutant profiling, secondary structure analysis, comparison with known structures of methyltransferases and isolation of catalytically inactive single mutants

The EcoRV DNA methyltransferase (M·EcoRV) is an -adeninemethyltransferase. We have used two different programs to predictthe secondary structure of M·EcoRV. The resulting consensusprediction was tested by a mutant profiling analysis. 29 neutralmutations of M·EcoRV were generated by five cycles ofrandom mutagenesis and selection for active variants to increasethe reliability of the prediction and to get a secondary structureprediction for some ambiguously predicted regions. The predictedconsensus secondary structure elements could be aligned to thecommon topology of the structures of the catalytic domains ofM·HhaI and M·TaqI. In a complementary approachwe have isolated nine catalytically inactive single mutants.Five of these mutants contain an amino acid exchange withinthe catalytic domain of M·EcoRV (Val20-Ala, Lys81Arg,Cys192Arg, Asp193Gly, Trp231Arg). The Trp231Arg mutant bindsDNA similarly to wild-type M·EcoRV, but is catalyticallyinactive. Hence this mutant behaves like a bona fide activesite mutant. According to the structure prediction, Trp231 islocated in a loop at the putative active site of M·EcoRV.The other inactive mutants were insoluble. They contain aminoacid exchanges within the conserved amino acid motifs X, IIIor IV in M·EcoRV confirming the importance of these regions.