Influence of the matrix porosity on the synthesis and adsorption behavior of dithiocarbamate styrenic resins toward zinc(II) and cadmium(II) ions

The dependence of the adsorption behavior toward Zn²⁺ and Cd²⁺ on the synthesis conditions of dithiocarbamate styrenic resins was investigated. We synthesized styrene–divinylbenzene copolymers with different kinds of porous structures by varying the divinylbenzene (DVB)‐to‐styrene ratio and the dilution degree of the monomers with n‐heptane. The porous structure of these materials was characterized. The introduction of the dithiocarbamate moiety on the copolymers followed a synthetic pathway based on the nitration reaction, reduction of the nitro group to the amino one, and finally, the addition of the amino group to CS₂. All of the synthesis steps were monitored by Fourier transform infrared spectroscopy. Only the addition reaction to CS₂ was greatly influenced by the copolymer porosity. The effect of the dilution degree on the reaction extension was more pronounced than the effect of the DVB content. The more porous materials with higher dithiocarbamate contents adsorbed a higher amount of ions in a faster way, with Zn²⁺ being preferable over Cd²⁺ ions. The difference between the Zn²⁺ and Cd²⁺ adsorption rates was enhanced with the copolymer porosity, and also enhanced was the difference between the amounts of ions adsorbed by the copolymer; this suggested that the selectivity toward these ions could be controlled by the copolymer porous structure. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Stakeholder perspectives on converting forest biomass to energy in Oregon, USA

Within the state of Oregon, USA, there is considerable interest in the possibility of converting forest biomass to energy. A number of studies have assessed the technical feasibility of forest biomass energy, but few have focused on social aspects, an important consideration in projects involving public forests. This study explores the social context of converting forest biomass to energy, using qualitative research methods. Semi-structured interviews were conducted with forty individuals representing nine different stakeholder groups. Information gained through interviews was used to understand stakeholder views on forest biomass energy, including their perspectives on potential barriers and opportunities in Oregon. Findings indicate the most challenging barrier will be access to long-term, consistent supply. A related challenge is the long history of contention between parties over forest products coming from public lands. However, findings also show that there are many areas of common ground between these groups that have historically been at odds, such as agreement on the necessity of restoration treatments in certain forest types, the by-product of which could be used for biomass generation. Potential conflicts still exist, for instance over projects in mixed conifer forests. Development of policies and projects through inclusive, collaborative approaches could alleviate controversies, potentially allowing more activities to move forward. Information provided by this research creates a foundation for discussions as forest biomass energy becomes an increasingly prominent issue in Oregon, the western USA, and other regions of the world.     

Study of Some Functional Properties of Casein: Effect of pH and Tryptic Hydrolysis

The trypsin was used to hydrolyze commercial casein at varied times and pH range. The functional properties studied were the emulsifying capacity (EC), the emulsifying activity index (EAI), and the emulsion stability (ES). The dispersed phase used was corn oil. The tryptic hydrolysis was beneficial to the solubility and EC of casein in practically all pH values and reaction times. In case of EAI, this same effect was less intense and was observed only in acid region (pH 3.0 to 5.0), while for ES the trypsin action was mainly deleterious in almost all pH range and reaction times.     

Stochastic particle packing with specified granulometry and porosity

This work presents a technique for particle size generation and placement in arbitrary closed domains. Its main application is the simulation of granular media described by disks. Particle size generation is based on the statistical analysis of granulometric curves which are used as empirical cumulative distribution functions to sample from mixtures of uniform distributions. The desired porosity is attained by selecting a certain number of particles, and their placement is performed by a stochastic point process. We present an application analyzing different types of sand and clay, where we model the grain size with the gamma, lognormal, Weibull and hyperbolic distributions. The parameters from the resulting best fit are used to generate samples from the theoretical distribution, which are used for filling a finite-size area with non-overlapping disks deployed by a Simple Sequential Inhibition stochastic point process. Such filled areas are relevant as plausible inputs for assessing Discrete Element Method and similar techniques.     

Morphological study on the reactivity of styrene‐divinylbenzene copolymers in a chloromethylation reaction

Styrene‐divinylbenzene (S‐DVB) copolymers with different kinds of porous structures were synthesized by aqueous suspension polymerization using n‐heptane as the pore forming agent. The amount of this solvent (monomer dilution degree) and the DVB content in the organic phase were varied. The combination of three different dilution degree values and three DVB contents yielded three series of copolymers with a variety of porous structures. The three series were composed by copolymers with pore diameters (D) in the following ranges: D < 500 Å, 500 < D < 1000 Å, and D > 1000 Å, respectively. The effect of synthesis conditions on the pore size distribution and on the copolymer matrix rigidity was evaluated. These copolymers were submitted to a chloromethylation reaction with a paraformaldehyde/gaseous HCl mixture in the presence of zinc chloride as a Lewis acid catalyst and 1,2‐dichloroethane as solvent. The effect of the copolymer porosity on the chloromethylation reaction extension was evaluated. It was possible to observe that a gel copolymer with a high swelling capacity in the reaction medium achieved the same chloromethylation yield observed for a high porous copolymer. This result thus indicates that, in the case of the chloromethylation reaction studied here, the high swelling capacity of the gel copolymer can counterbalance its limited surface area, turning this type of polymer structure as reactive as a macroporous one. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Kinetic study of polyurethane synthesis using different catalytic systems of Fe,Cu, Sn,and Cr

This work presents a comparative study between alternative catalytic systems, metal‐β‐diketones complexes (iron, copper, chromium, and tin), and the commercial catalyst dibutyltin dilaurate, DBTDL, in the polyurethanes synthesis obtained from isophorone diisocyanate (IPDI) and polyols as polypropyleneglycol/diethyleneglycol and 1,6‐hexanodiol polyadipate (polyester A‐Mn = 2000 g/mol and polyester B‐Mn = 1000 g/mol) reactions. The polyurethanes synthesis was followed by the IPDI consumption in time, verified by infrared spectroscopy (FTIR) through the decrease of free NCO characteristic band at 2300–2200 cm^?1. The FTIR data was used to determine the polyurethanes formation kinetic behavior. It was verified that for the reactions with polyethers excess, DBTDL catalyst was more effective when compared to metal‐β‐diketones complexes, while for the reactions with polyester, A and B, the metal‐β‐diketones complexes were more effective. © 2009 Wiley Periodicals, Inc. JAppl Polym Sci, 2010     

Cloning and characterization of the guinea pig eosinophil eotaxin receptor, C-C chemokine receptor-3: blockade using a monoclonal antibody in vivo

Certain C-C chemokines, signaling via the eotaxin receptor C-C chemokine receptor-3 (CCR3), are thought to be central mediators of eosinophil accumulation in allergic inflammation. To investigate the role of CCR3 in vivo, we cloned the guinea pig eotaxin receptor (guinea pig CCR3) from a genomic DNA library. We isolated a single-exon open reading frame coding for a 358-amino acid chemokine receptor protein with 67 and 69% homology to human and murine CCR3, respectively. When expressed in stable transfectants, this receptor bound 125I-labeled guinea pig eotaxin, 125I-labeled human monocyte chemotactic protein-3, and 125I-labeled human RANTES. In chemotaxis assays, guinea pig CCR3 transfectants responded only to guinea pig eotaxin, with a maximal effect at 100 nM. mAbs were raised that bound selectively to both guinea pig CCR3 transfectants and guinea pig eosinophils. One of these mAbs, 2A8, blocked both ligand binding to transfectants and their chemotaxis in response to eotaxin. The Ab also inhibited chemotaxis and the elevation of cytosolic calcium in guinea pig eosinophils in response to eotaxin. F(ab')2 fragments of 2A8 were prepared that retained the ability to inhibit eosinophil calcium responses to eotaxin. Pretreatment of (111)In-labeled eosinophils in vitro with F(ab')2 2A8 selectively inhibited their accumulation in response to eotaxin in vivo. These data demonstrate that functional blockade of eosinophil chemokine receptors can be achieved in vivo and provide further support for the development of novel anti-inflammatory drugs targeting eosinophil recruitment through chemokine receptor antagonism.     

A New Application of the Severity Factor Kinetic Model: Thermal Plasma Treatment of Black Liquor

The kinetic analysis of the treatment of black liquor by a thermal process can be performed in the conventional overall kinetic approach. However, while the detailed reaction mechanism remains unknown, the experimental analysis of black liquor treatment by submerged plasma demonstrates that the operating conditions (catalyst, plasma gas, temperature…) modify the kinetics and render this approach inefficient. The phenomenological approach based on the severity factor developed for the kinetic analysis of lignocellulose decomposition, is then proposed as an alternative to the conventional approach. The 3‐parameters model is validated for decomposition of formic acid and for sulfur oxidation.     

Delineating the construct network of the Personnel Reaction Blank: Associations with externalizing tendencies and normal personality.

Integrity testing has long been utilized in personnel selection to screen for tendencies toward counterproductive workplace behaviors. The construct of externalizing from the psychopathology literature represents a coherent spectrum marked by disinhibitory traits and behaviors. The present study drew on a sample of male and female undergraduates to examine the construct network of the Personnel Reaction Blank (PRB; H. G. Gough, R. D. Arvey, & P. Bradley, 2004), a measure of integrity, in relation to externalizing as well as normal-range personality constructs assessed by the Multidimensional Personality Questionnaire (MPQ; A. Tellegen & N. G. Waller, 2008). Results revealed moderate to strong associations between several PRB scales and externalizing, which were largely accounted for by MPQ traits subsumed by Negative Emotionality and Constraint. After accounting for MPQ traits in the prediction of externalizing, a modest predictive increment was achieved when adding the PRB scales, particularly biographical indicators from the Prosocial Background subscale. The findings highlight externalizing as a focal criterion for scale development in the integrity testing literature and help delineate the construct network of the PRB within the domains of personality and psychopathology. (PsycINFO Database Record (c) 2011 APA, all rights reserved)