Nutritional knowledge and consumption frequency of foods--a case study

The relationship between nutritional knowledge and the consumption frequency of preferred food-types was studied among one sample of Uruguayan consumers. A locally-adapted version of Parmenter & Wardle's General Nutrition Knowledge Questionnaire and a food consumption survey based on 39 food groups were completed by a total of 270 participants. Cluster Analysis enabled the identification of two clusters showing different levels of nutritional knowledge--cluster 1 (n = 177) and cluster 2 (n = 93), providing an average of 73.6% and 52.9% of correct answers, respectively. These clusters differed significantly (p < or = 0.05) in age and educational distribution--cluster 1 was composed mainly by older adults and persons with a higher educational level. A number of areas were identified where nutritional knowledge was extremely poor, as was the case with the recommended daily fruit and vegetable intake and the caloric content of the nutrients. Overall, nutritional knowledge was found to have a positive influence on food preferences and consumption frequency, those participants with a higher nutritional knowledge reporting a higher consumption of fruits, vegetables and low-fat products, in addition to a lower consumption of high-fat and high-sugar foods.     

Kinetics of glucose decomposition in formic acid

Cellulose is abundantly available in the form of forestry and agricultural lignocellulosic residues. These residues offer the most potential source for the production of cellulosic glucose, which is a prerequisite for the sustainable production of glucose-based fuels and chemicals. Acid catalysis is one path to lignocellulosic glucose and further to its dehydration end products. Furthermore, many studied lignocellulose pretreatment methods for enzymatic hydrolysis are carried out in acidic conditions, in which the unwanted release of hemicellulose-based glucose and its further reactions to harmful end products are possible. Thus, in order to maximize glucose production from non-food cellulosic raw materials, data on the kinetics of cellulose decomposition and formation rates of end products are required. Glucose decomposition is a complex reaction system that has often been modelled with empirical, simplified models. In this study, a kinetic model was developed for glucose decomposition in formic acid solution. The experimentation was carried out in batch reactors at 180-220 °C in 5-20% (w/w) formic acid. The model developed relies on a mechanistic step through an unknown substance and gives excellent correspondence to the experimental data despite the pseudo-elementary nature of the model structure.     

Water�CGas Shift and CO Methanation Reactions over Ni�CCeO2(111) Catalysts

X-ray and ultraviolet photoelectron spectroscopies were used to study the interaction of Ni atoms with CeO₂(111) surfaces. Upon adsorption on CeO₂(111) at 300 K, nickel remains in a metallic state. Heating to elevated temperatures (500?C800 K) leads to partial reduction of the ceria substrate with the formation of Ni²⁺ species that exists as NiO and/or Ce_1?xNi_xO_2?y. Interactions of nickel with the oxide substrate significantly reduce the density of occupied Ni 3d states near the Fermi level. The results of core-level photoemission and near-edge X-ray absorption fine structure point to weakly bound CO species on CeO₂(111) which are clearly distinguishable from the formation of chemisorbed carbonates. In the presence of Ni, a stronger interaction is observed with chemisorption of CO on the admetal. When the Ni is in contact with Ce⁺³ cations, CO dissociates on the surface at 300 K forming NiC_x compounds that may be involved in the formation of CH₄ at higher temperatures. At medium and large Ni coverages (>0.3 ML), the Ni/CeO₂(111) surfaces are able to catalyze the production of methane from CO and H₂, with an activity slightly higher than that of Ni(100) or Ni(111). On the other hand, at small coverages of Ni (<0.3 ML), the Ni/CeO₂(111) surfaces exhibit a very low activity for CO methanation but are very good catalysts for the water?Cgas shift reaction.     

ATR-FTIR Study of the Decomposition of Acetic Anhydride on Fosfotungstic Wells–Dawson Heteropoly Acid Using Concentration-Modulation Excitation Spectroscopy

The decomposition of acetic anhydride in liquid phase on a fosfotungstic Wells–Dawson heteropoly acid (HPA) was investigated by in situ ATR-FTIR spectroscopy. Transient and concentration-modulation excitation spectroscopy (MES) experiments in combination with phase-sensitive detection (PSD) were used to monitor the solid–liquid interface. The MES method is based on the periodic variation of a parameter of the reaction media such as, the reactant concentration. That periodic alteration causes varying infrared signals of the surface adsorbed species that are subsequently demodulated with the PSD methodology. Thus, the separation of the static signals from the changing ones is achieved, and species with different response can be observed in the spectra. Using MES-PSD coupled with ATR-FTIR, acetic anhydride was observed to decompose to acetic acid, acetate and acyl [CH₃C(O)⁺] species, involving Brønsted acid sites of the HPA catalyst. The CH₃C(O)⁺ is a very unstable intermediate species and it is the key intermediate in the Friedel–Crafts acylation reactions. Moreover, the acetate groups are spectator species since remain strongly adsorbed on the catalyst surface and do not further react.     

lordif: An R Package for Detecting Differential Item Functioning Using Iterative Hybrid Ordinal Logistic Regression/Item Response Theory and Monte Carlo Simulations

Logistic regression provides a flexible framework for detecting various types of differential item functioning (DIF). Previous efforts extended the framework by using item response theory (IRT) based trait scores, and by employing an iterative process using group-specific item parameters to account for DIF in the trait scores, analogous to purification approaches used in other DIF detection frameworks. The current investigation advances the technique by developing a computational platform integrating both statistical and IRT procedures into a single program. Furthermore, a Monte Carlo simulation approach was incorporated to derive empirical criteria for various DIF statistics and effect size measures. For purposes of illustration, the procedure was applied to data from a questionnaire of anxiety symptoms for detecting DIF associated with age from the Patient-Reported Outcomes Measurement Information System.     

Rigorous synthesis and simulation of complex distillation networks

Recent insights for better understanding the thermodynamic foundations of separation processes have renewed the interest in exploring energy‐efficient distillation networks. Complex column networks have substantial potential for energy savings over conventional configurations. This article introduces a computational algorithm for synthesizing such complex energy‐efficient networks. A robust feasibility criterion drives the selection of design specification and operating conditions. It will be shown that columns composed of sections whose liquid stage composition profiles have no gaps are realizable. To prove the rigor of design computations, numerous separation networks were synthesized and validated with the Aspen flowsheet simulator. By using our computational results as input, AspenPlus simulations converged in a few iterations. Our method builds on temperature collocation, a thermodynamically motivated search method for determining feasible operating conditions and design details for achieving the desired product targets. Our findings suggest that significant energy savings can be realized with rigorous complex networks synthesis for industrial separation problems. © 2010 American Institute of Chemical Engineers AIChE J, 2011     

T cells enhance gold nanoparticle delivery to tumors <Emphasis Type="Italic">in vivo</Emphasis>

Gold nanoparticle-mediated photothermal therapy (PTT) has shown great potential for the treatment of cancer in mouse studies and is now being evaluated in clinical trials. For this therapy, gold nanoparticles (AuNPs) are injected intravenously and are allowed to accumulate within the tumor via the enhanced permeability and retention (EPR) effect. The tumor is then irradiated with a near infrared laser, whose energy is absorbed by the AuNPs and translated into heat. While reliance on the EPR effect for tumor targeting has proven adequate for vascularized tumors in small animal models, the efficiency and specificity of tumor delivery in vivo, particularly in tumors with poor blood supply, has proven challenging. In this study, we examine whether human T cells can be used as cellular delivery vehicles for AuNP transport into tumors. We first demonstrate that T cells can be efficiently loaded with 45 nm gold colloid nanoparticles without affecting viability or function (e.g. migration and cytokine production). Using a human tumor xenograft mouse model, we next demonstrate that AuNP-loaded T cells retain their capacity to migrate to tumor sites in vivo. In addition, the efficiency of AuNP delivery to tumors in vivo is increased by more than four-fold compared to injection of free PEGylated AuNPs and the use of the T cell delivery system also dramatically alters the overall nanoparticle biodistribution. Thus, the use of T cell chaperones for AuNP delivery could enhance the efficacy of nanoparticle-based therapies and imaging applications by increasing AuNP tumor accumulation.     

Enhanced electrochemical reduction of hydrogen peroxide on silver paste electrodes modified with surfactant and salt

The modification of silver paste electrodes with a combination of dodecylbenzenesulfonic acid and KCl has been shown to lead to significant enhancements of the electrochemical reduction of hydrogen peroxide. The catalytic enhancement was shown to be dependent on the concentration of the surfactant/salt solution, which resulted in increases of some 80-fold in amperometric response to hydrogen peroxide at −0.1 V vs Ag/AgCl, pH 6.8 over unmodified silver paste. Physical analysis showed modifications to both the surface morphology and chemical composition of the silver paste electrode surface. However, BET and electrochemical analysis revealed no significant change in surface area. It is suggested that the enhanced catalysis may result from the formation of stabilised surfactant/salt structures at the metal electrode surface. The electrode was also shown to be suitable for the amperometric detection of hydrogen peroxide with a limit of detection of 1.1 × 10⁻⁶ M (S/N = 3).     

Synthesis of freestanding HfO<Subscript>2</Subscript> nanostructures

Two new methods for synthesizing nanostructured HfO₂ have been developed. The first method entails exposing HfTe₂ powders to air. This simple process resulted in the formation of nanometer scale crystallites of HfO₂. The second method involved a two-step heating process by which macroscopic, freestanding nanosheets of HfO₂ were formed as a byproduct during the synthesis of HfTe₂. These highly two-dimensional sheets had side lengths measuring up to several millimeters and were stable enough to be manipulated with tweezers and other instruments. The thickness of the sheets ranged from a few to a few hundred nanometers. The thinnest sheets appeared transparent when viewed in a scanning electron microscope. It was found that the presence of Mn enhanced the formation of HfO₂ by exposure to ambient conditions and was necessary for the formation of the large scale nanosheets. These results present new routes to create freestanding nanostructured hafnium dioxide.