Colour category foci of Munsell colour spectra revealed by two computational methods

Colour names and psychophysical colour categories play an important role on human communication. For several application areas from computer vision to Internet shopping, it would be useful to manage colour information using methods of computational colour naming in a similar manner as people do in their everyday life. In this study, we applied two computational methods, the nonnegative matrix factorization and self‐organizing maps, to derive basic colours from a spectral database of Munsell colours, and a subset of it. The subset was generated to include only the most saturated samples of each Munsell Hue and Munsell Value pair of the original database. Using both the methods and both the databases, we calculated the sets of 3, 4, 6, and 8 basis vectors to represent the focal colours of colour categories. Colour names of the calculated focal colours were investigated using the results by Sturges and Whitfield as a reference. Nonnegative matrix factorization yields calculated colours more compatible with human basic colours, but the spectra generated by self‐organizing maps are more similar to natural spectra as their shape is smoother. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2010     

Polycyclic Aromatic Hydrocarbons from Candiota (South Brazilian) Coal Extracts

The bitumen composition of Candiota coal (south Brazil) was investigated. Coal bitumen was produced by Soxhlet extraction using toluene. Two chromatographic techniques were tested for bitumen fractionation: adsorption liquid chromatography on silica (ALCS) and adsorption liquid chromatography on alumina (ALCA). Results were compared in terms of the quality and quantity of hydrocarbons isolated. Several linear saturated hydrocarbons were found in the range of 14 to 33 carbons. Pyrene, chrysene, and other polycyclic hydrocarbons with recognized mutagenic and carcinogenic properties were found in the aromatic fractions. Chromatographic methodology using alumina shows better results in the fractionation of bitumen.     

Bioleaching and recovery of metals from final slag waste of the copper smelting industry

Solid waste from the copper smelting industry may be harmful if disposed of in the environment, but it may be a valuable resource if metals can be recovered. The purpose of this study was to evaluate the acid bioleaching of metals from a sample of final smelter slag and the recovery of metals from the leach liquors. Bioleaching was tested in a continuously stirred tank reactor (CSTR) at 20-25 °C with 5% pulp density (particle size 75% <47 μm). The yields of metal solubilization after 29 days of contact were 41% Fe, 62% Cu, 35% Zn and 44% Ni. Metals were precipitated in a separate CSTR by titrating the leach liquors with sulfide-rich effluent from a sulfate-reducing fluidized-bed reactor (FBR) (25 °C) to desired pH values. Over 98% of the Cu precipitated at pH ? 2.8 and over 99% of the Zn precipitated at pH ? 3.9. The precipitation of Ni and Fe required higher pH values and was less efficient than Cu and Zn recovery. In addition, bulk precipitation of metals was also tested by feeding the leach liquor directly to another sulfate-reducing FBR. In order to reduce its toxicity and maintain stable sulfate reduction performance in the FBR, the leach liquor had to be diluted ten-fold and the pH adjusted from 0.6 to approximately 4.     

Object-oriented design of process line simulation and optimization—A case study in papermaking

Simulation-based optimization for industrial process lines is discussed in this paper. Our approach combines multidisciplinary modeling, modern sensitivity analysis methodology as well as multiobjective optimization by means of object-oriented software design principles. As a result, a simulation and optimization approach that can be extended and modified due to users’ needs can be developed. Our approach is illustrated by a real-world example from papermaking industry.     

Inhalation exposure to nanosized and fine TiO2 particles inhibits features of allergic asthma in a murine model

Background

Nowadays, effects of fine particulate matter (PM_2.5) are well-documented and related to oxidative stress and pro-inflammatory response. Nevertheless, epidemiological studies show that PM_2.5 exposure is correlated with an increase of pulmonary cancers and the remodeling of the airway epithelium involving the regulation of cell death processes. Here, we investigated the components of Parisian PM_2.5 involved in either the induction or the inhibition of cell death quantified by different parameters of apoptosis and delineated the mechanism underlying this effect.

Results

In this study, we showed that low levels of Parisian PM_2.5 are not cytotoxic for three different cell lines and primary cultures of human bronchial epithelial cells. Conversely, a 4 hour-pretreatment with PM_2.5 prevent mitochondria-driven apoptosis triggered by broad spectrum inducers (A23187, staurosporine and oligomycin) by reducing the mitochondrial transmembrane potential loss, the subsequent ROS production, phosphatidylserine externalization, plasma membrane permeabilization and typical morphological outcomes (cell size decrease, massive chromatin and nuclear condensation, formation of apoptotic bodies). The use of recombinant EGF and specific inhibitor led us to rule out the involvement of the classical EGFR signaling pathway as well as the proinflammatory cytokines secretion. Experiments performed with different compounds of PM_2.5 suggest that endotoxins as well as carbon black do not participate to the antiapoptotic effect of PM_2.5. Instead, the water-soluble fraction, washed particles and organic compounds such as polycyclic aromatic hydrocarbons (PAH) could mimic this antiapoptotic activity. Finally, the activation or silencing of the aryl hydrocarbon receptor (AhR) showed that it is involved into the molecular mechanism of the antiapoptotic effect of PM_2.5 at the mitochondrial checkpoint of apoptosis.

Conclusions

The PM_2.5-antiapoptotic effect in addition to the well-documented inflammatory response might explain the maintenance of a prolonged inflammation state induced after pollution exposure and might delay repair processes of injured tissues.     

Bacterial community composition and structure of biofilms developing on nanofiltration membranes applied to wastewater treatment

The structure and microbial communities of biofilms developing on cross-flow nanofiltration (NF) membranes at different temperatures (20, 25 or 34 degrees C) and operation lengths (8h-24days) were studied. Feedwater comprised tertiary quality wastewater effluent or synthetic media mimicking effluents of intermediate quality. After each run, the membranes were autopsied for bacterial enumeration, bacterial community composition and microscopy visualization (SEM, CLSM and AFM/NSOM). Community composition was analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) coupled with sequence analysis of 16S rRNA gene fragments from dominant bands. Deposition of polysaccharides and initial bacterial colonization were observed within 8h, whereas developed biofilms markedly affecting membrane permeability were evident from days 2-3 onwards. Regardless of applied conditions, the heterotrophic plate counts in the biofilm were 3-4x10(6)CFU/cm(2) and the thickness of the biofouling layer was 20-30microm. From a total of 22 sequences obtained from 14 independent experiments, most species identified were Gram negative (19 of 22 sequences). Proteobacteria were found to be a prevalent group in all cases (16 of 22 sequences) and among it, the beta-subclass was the most predominant (8 sequences), followed by the gamma-subclass (5 sequences). Pseudomonas/Burkholderia, Ralstonia, Bacteroidetes and Sphingomonas were the dominant groups found in most cases. Even though the microbial population might be important with respect to biofouling patterns, membrane permeability decline seems to be more substantially influenced by the formation and accumulation of exopolymeric substances (EPS).     

Arabinoxylan/nanofibrillated cellulose composite films

There is an increasing interest in substituting petroleum based polymer films, for food packaging applications, with films based on renewable resources. In many of these applications, low oxygen permeability and low moisture uptake of films are required, as well as high enough strength and flexibility. For this purpose, rye arabinoxylan films reinforced with nanofibrillated cellulose was prepared and evaluated. A thorough mixing of the components resulted in uniform films. Mechanical, thermal, structural, moisture sorption and oxygen barrier characteristics of such films are reported here. Reinforcement of arabinoxylan with nanofibrillated cellulose affected the properties of the films positively. A decrease in moisture sorption of the films, as well as an increase in stiffness, strength and flexibility of the films were shown. From these results and dynamic FTIR spectra, a strong coupling between reinforcing cellulose and arabinoxylan matrix was concluded. Oxygen barrier properties were equal or better as compared to the neat rye arabinoxylan film. In general, the high nanofibrillated cellulose containing composite film, i.e. 75 % NFC, showed the best properties.     

Mutational Analysis of the C–C Bond Cleaving Enzyme Phloretin Hydrolase from Eubacterium ramulus

Phloretin hydrolase from Eubacterium ramulus (Phy) catalyzes the hydrolysis of the dihydrochalcone phloretin to phloroglucinol and phloretic acid, performing a formal retro- Friedel–Crafts acylation reaction on its substrate. Its closest sequence homolog, of 25 % amino acid sequence identity, is diacetyl phloroglucinol hydrolase (Phlg) from Pseudomonas fluorescens, which catalyses a similar, hydrolytic, de-acylation of its substrate. The structure of Phlg has been determined and a catalytic mechanism proposed (J Biol Chem 285:4603–4611, 2010). In order to compare the catalytic characteristics of Phy with Phlg, the gene encoding Phy was expressed and the enzyme purified and crystallised. An X-ray fluorescence scan identified zinc within the crystals. A homology model of Phy, based on the structure of Phlg (PDB code 3HWP), informed the construction of a point mutant library of the enzyme, targeting residues shared with Phlg that are thought to be involved in zinc binding and the recognition of acyl and phenol functionality on the aromatic ring of the substrates. Mutation of His123, His251, Glu154 and Glu255 (conserved zinc binding residues) resulted in variants that were either poorly expressed, or of much reduced activity; Mutation of Tyr115 and His203, thought to bind the phenol groups in the 1-and 3-positions of the phloroglucinol ring respectively, resulted in variants of 15-fold reduced activity and an inactive variant. These results are suggestive of conservation of some aspects of mechanism and substrate recognition between Phy and Phlg, and of the catalytic characteristics of Zn-dependent C–C hydrolases of this type in general.     

Efficient Cisplatin Pro‐Drug Delivery Visualized with Sub‐100 nm Resolution: Interfacing Engineered Thermosensitive Magnetomicelles with a Living System

Temperature‐responsive magnetic nanomicelles can serve as thermal energy and cargo carriers with controlled drug release functionality. In view of their potential biomedical applications, understanding the modes of interaction between nanomaterials and living systems and evaluation of efficiency of cargo delivery is of the utmost importance. In this work, we investigate the interaction between the hybrid magnetic nanomicelles engineered for controlled platinum complex drug delivery and a biological system at three fundamental levels: subcellular compartments, a single cell and whole living animal. Nanomicelles with polymeric P(NIPAAm‐co‐AAm)‐b‐PCL core‐shell were loaded with a hydrophobic Pt(IV) complex and Fe₃O₄ nanoparticles though self‐assembly. The distribution of a platinum complex on subcellular level is visualized using hard X‐ray fluorescence microscopy with unprecedented level of detail at sub‐100 nm spatial resolution. We then study the cytotoxic effects of platinum complex‐loaded micelles in vitro on a head and neck cancer cell culture model SQ20B. Finally, by employing the magnetic functionality of the micelles and additionally loading them with a near infrared fluorescent dye, we magnetically target them to a tumor site in a live animal xenografted model which allows to visualize their biodistribution in vivo.