Extensional viscosity measurements and characterization of poly (vinyl chloride‐co‐vinyl acetate) plastisols and foams

The foaming of PVC‐VA [Poly (vinyl chloride‐co‐vinyl acetate)] plastisols is a complex combination of processes involving the simultaneous curing of the paste with the evolution of gases caused by the decomposition of the chemical blowing agent. The extensional viscosity is a fundamental characteristic of the material, responsible for the behavior of the system when undergoing the extensional stress produced by the released gases. Nevertheless, such changes have not been considered to the same extent as the complex viscosity evolution or the thermal processes suffered by PVC‐VA plastisols. The objective of the present work is to study the extensional viscosity of the PVC‐VA plastisols prepared with three plasticizers of similar structure, but with different curing and rheological behavior in order to investigate its influence on the quality of the foams obtained. Extensional viscosity measurements under forced prestretch conditions revealed that depending on the structure and consequently on the compatibility of the plasticizer used, each plastisol develops its properties and structure accordingly. DINCH plasticizer (Diisononyl cyclohexane‐1,2‐dicarboxylate presenting alicyclic ring) seems to be the less compatible compared with the other two studied (both presenting aromatic rings) according to its behavior during the curing and foaming processes and may not be able to withstand the pressure evolved by the released gases during the foaming process yielding foams of poorer quality. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Development of a rapid, non-destructive method for egg content determination in dry pasta using FT-NIR technique

A quick, non-destructive method, based on Fourier transform near-infrared (FT-NIR) spectroscopy for egg content determination of dry pasta is presented. Multivariate calibration was carried out by using partial least squares (PLS) regression. A calibration set of 108 samples, a validation set of 22 samples and a prediction set of 11 samples of egg pasta were used. The diffuse reflection spectra of different types of pastas were measured by FT-NIR analyzer in the 800-2500 nm spectral range. The optimal results for egg content (root mean square error of prediction (RMSEP) = 0.7; R² = 90.7, Rank = 4) were obtained when the spectra were subjected to the first derivation combined with multiplicative scatter correction (MSC) and smoothing. Egg content was determined from FT-NIR results by introducing a mathematical correction step.     

Mechanisms of enterohemorrhagic Escherichia coli spread along the food-chain and precautionary measures

Enterohemorrhagic Escherichia coli (EHEC) are food-borne pathogens implicated in large outbreaks and sporadic cases of bloody diarrhea and the hemolytic uremic syndrome. The main reservoir of EHEC is the intestinal tract of ruminants, in particular cattle. Feces containing these bacteria may act as a source of contamination for the environment and particularly for a variety of foods. E. coli O157:H7 as well as other EHEC-serotypes have been isolated from domestic ruminants and non-ruminant farm animals as well as products produced from them, but also from drinking water, vegetables and dairy products. The main transmission pathway of the pathogens is the ingestion of raw or undercooked contaminated food but human infection can also occur by person-to-person transmission. This article will focus on the prevalence and spread of EHEC by vegetable foods, especially the less common EHEC transmission sources sprouts and leafy greens. It will discuss precautionary measures against the spread of EHEC in food at all stages of the food chain: the primary production, the industrial processing, the retailing as well as the consumer.     

A structural study of cadmium interaction with aquatic microorganisms

The molecular mechanisms of cadmium toxicity for aquatic phototrophic microorganisms, reversible adsorption on the surface, and cellular uptake during growth were investigated by combining batch macroscopic experiments with atomic-level in situ Cd K-edge X-ray absorption fine structure spectroscopy. The following species were examined: marine planktonic (Skeletonema costatum, Thalassiossira weissflogil) and freshwater periphytic (Navicula minima, Achnanthidium minutissum) diatoms, cyanobacteria (Gloeocapsa sp.), anoxygenic phototrophic bacteria (Rhodopseudomonas palustris), and freshwater diatom-dominated biofilms. Upon short-term adsorption at the freshwater diatoms and cyanobacteria cell surface from a NaNO3 or NaCl solution, Cd is octahedrally coordinated by oxygen at an average distance of 2.27 +/- 0.02 angstroms and is associated with carboxylate groups. The atomic environment of cadmium incorporated into freshwater diatoms during long-term growth (operationally defined as Cd nonextracted by EDTA) is similar to that of adsorbed metal in terms of Cd-O first-shell distances and coordination numbers. Contrasting speciation is found for Cd incorporated into marine diatoms and adsorbed onto phototrophic anoxygenic bacteria R. palustris, where Cd is coordinated with three to five oxygen/nitrogen atoms and one to three sulfur atoms in the first atomic shell, likely in the form of cysteine/hystidine complexes or Cd-thiolate clusters. The Cd association with sulfhydryl groups in marine planktonic diatoms and anoxygenic bacteria is an important feature of Cd binding which can be useful for assessing the bioavailability of this metal.     

Optimization of the sorghum malting process for pito production in Ghana

Pito is an alcoholic beverage obtained through a yeast (Saccharomyces cerevisiae) fermentation of wort extracted from sorghum (Sorghum bicolor L. Moench) malt. The malting conditions of sorghum are thought to influence the quality characteristics of the malt, and subsequently the quality of the pito obtained from it. Studies were carried out on a local sorghum cultivar grown in Ghana – chireh, to optimize the conditions for malting conditions for pito production in Ghana. A 3³ full factorial experimental design was replicated with steeping times of 12, 16 and 22 h, germination times of 3, 4 and 5 days, and malt drying temperatures of 30, 40 and 50 °C as factors. Diastatic power, extract yield, attenuation limit and free amino nitrogen were determined. Germination duration significantly affected diastatic power and free amino nitrogen (p < 0.001). Extract yield was also significantly influenced by germination duration (p = 0.001). The germination time, steeping time and drying temperature had no significant effect on the attenuation limit. The optimal conditions for malting this specific cultivar grown in Ghana to obtain critical malt quality indices are 12.0–12.5 h steeping, 5 days of germination at 30 °C and drying at 40 °C. Free amino nitrogen levels in all treatments were higher than the minimum requirement for good yeast nutrition and fermentation. Copyright © 2015 The Institute of Brewing & Distilling     

Theoretical claims necessitate basic research: Reply to Gawronski, Lebel, Peters, and Banse (2009) and Nosek and Greenwald (2009).

The authors of this reply article note that B. Gawronski, E. P. LeBel, K. R. Peters, and R. Banse (see record 2009-05290-002) (a) expressed agreement in their comment with the analysis put forward in the target article (J. De Houwer, S. Teige-Mocigemba, A. Spruyt, & A. Moors) (see record 2009-05290-001) and (b) pointed to a further implication for the way in which the implicitness of a measure should be examined. The current authors note that B. A. Nosek and A. G. Greenwald (see record 2009-05290-003), on the other hand, raised questions in their comment about the definition of the concept “implicit” in the target article, arguing for a fundamentally different approach to measurement that emphasizes not theoretical understanding but usefulness for predicting behavior. In this reply, the current authors respond to these comments and argue that when theoretical claims are made about measures, these claims should be backed up with appropriate evidence. In the absence of basic research, measures and their relation to behavior can only be described. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Child maltreatment polyvictimization: Rates and short-term effects on adjustment in a representative Hong Kong sample.

Objective: This article examines the unique effects of multiple forms of victimization, namely child abuse and neglect (CAN) and exposure to parental intimate partner violence (IPV), on children's self-blame, feelings of being threatened, self-esteem, and ability to control anger. Method: The cross-sectional study recruited a population-based sample of 2,062 children aged 12–17 years in Hong Kong. Structured questionnaires were used to collect data from the children. The prevalence rate of the co-occurrence of exposure to IPV and CAN in the Chinese population, and the unique impacts of exposure to IPV and CAN on children were examined. Results: The results show that 13.1% of the children had experienced CAN, and 6.5% had witnessed parental IPV. Among those families characterized by IPV, 61.1% were involved in child abuse in the preceding year of the study. Participants who had experienced both CAN and exposure to parental IPV reported lower levels of self-esteem and higher rates of being aggressive and violent, and feeling threatened. These children also reported the highest levels of feeling that their well-being was threatened and of blaming themselves for parental violence and parental discipline. Conclusions: The findings reemphasize the important need for public policy on child and youth victimization that encourages social workers and Child Protective Services to screen for child polyvictimization in cases of suspected/reported child abuse. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive and neuropathologic correlates of Stroop Color-Word Test performance in Alzheimer's disease.

The Stroop Color-Word Test (SCWT; C. Golden, 1978) was examined in 59 patients with probable Alzheimer's disease (AD) and in 51 demographically comparable normal control (NC) participants. AD patients produced significantly larger Stroop interference effects than NC participants, and level of dementia severity significantly influenced SCWT performance. Principal -components analyses demonstrated a dissociation in the factor structure of the Stroop trials between NC participants and AD patients, suggesting that disruption of semantic knowledge and speeded verbal processing in AD may be a major contributor to impairment on the incongruent trial. Results of clinicopathologic correlations in an autopsy-confirmed AD subgroup further suggest the invocation of a broad network of integrated cortical regions and executive and language processes underlying successful SCWT performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Characterization of clay scales forming in Philippine geothermal wells

Smectite scales occur in 24 out of 36 blocked wells located in Tongonan, Palinpinon and Bacon-Manito. These comprise 2–85% of the well scales and form at depths of 36–2620 m. where measured and fluid inclusion temperatures are 41–320°C. Most, however, occur below the production casing shoe where temperatures are 230°C, often at depths coinciding with aquifers. The clay scales are compositionally and structurally different from the bentonite used in drilling, which is essentially a sodium-rich montmorillonite. The clay deposits are expanding, generally disordered, and combine the characteristics of a montmorillonite, saponite and vermiculite in terms of reaction to cationic exchange treatments, structure and composition. Six types of clay scales were identified, but the predominant one, comprising 60–100% of the clay deposits in a well, is Mg- and Fe-rich and referred to as a vermiculitic species. The crystallinity, degree of disorder, textures, optical characteristics, structure and relative amounts of structural Al, Mg and Fe vary with time, temperature and fluid composition, but not with depth and measured pressure. Despite its variance from bentonite characteristics one of the dominant suggested mechanisms for clay scale formation uses the drilling mud in the well as a substrate, from which the Mg and Fe-rich clay evolves. Another important possible mechanism for formation of the clay scale is the precipitation of the clays from hydrothermal fluids, wherein Mg and Al appear to be the limiting elements. Other, less important, mechanisms of formation are: alteration of chloritized cuttings in the well to the vermiculitic species and the probable introduction of smectite from the formation.