New ways of utilizing soy in human diets in Latin America

Two simple, practical processes for the preparation of diverse products from soybeans for use by needy groups in Mexico and Latin America are described. One of 13 papers presented in the symposium, “Soy Protein,” at the AOCS Spring Meeting, Mexico City, April 1974.     

Methane steam reforming modeling in a palladium membrane reactor

A mathematical model of a membrane reactor used for methane steam reforming was developed to simulate and compare the maximum yields and operating conditions in the reactor with that in a conventional fixed bed reactor. Results show that the membrane reactor resents higher methane conversion yield and can be operated under milder conditions than the fixed bed reactor, and that membrane thickness is the most important construction parameter for membrane reactor success. Control of the H₂:CO ratio is possible in the membrane reactor making this technology more suitable for production of syngas to be used in gas-to-liquid processes (GTL).     

Modulating influence of dietary lipid intake on the prostaglandin system in adult men

We evaluated the effect of moderate dietary changes on the prostaglandin system by measuring the urinary excretion of 7α-hydroxy-5,11-dioxo-tetranorprostane-1,16-dioic acid (PGE-M). In a crossover design, twenty-four free-living male subjects in good health (24 to 54 years of age) were fed two diets: (i) Regular (R) diet, 41% energy (en%) from fat, P/S 0.59, M/S 0.96; (ii) Experimental (E) diet, 19 en% from fat, P/S 1.31, M/S 1.48. Diet R contained 13.9 g/day of neutral detergent fiber (NDF) and about 600 mg/day of cholesterol per 3200 kcal; Diet E contained 35.5 g/day NDF and about 280 mg/day cholesterol. Each controlled-diet period lasted ten weeks. The menu cycle was 7 days, and all diets were calculated to provide adequate amounts of essential nutrients. The PGE-M excretion rates were determined in 24-hr urine by stable-isotope dilution gas chromatography-mass spectrometry in the selected ion-monitoring mode. Low-fat Diet E, with an intake of 6.6 en% from polyunsaturates, was associated with an average 14.2% reduction in PGE-M daily output, compared to high-fat Diet R with a 9.3 en% from polyunsaturates (P=0.046). These results support the view that dietary lipid changes can significantly alter thein vivo production of E-series prostaglandins. We cannot conclude, however, if this apparent diet effect was brought about by the change in linoleate intake alone or was the result of complex biochemical interactions among individual fatty acids, both saturated and unsaturated.     

Influence of molecular weight on the crystallization of poly(vinylidene fluoride)

Five samples of Poly (vinylidene fluoride) with a molecular weight from 45,000 to 260,000 were analyzed by means of FT-IR spectroscopy in order to study the influence of molecular weight on the crystallization process. The spectra of films obtained from methylethylketone solutions revealed the prevalence of form II () in the case of lower and of form III () in the higher molecular weight samples. The amount of form III was found to increase as the Mv decreased and as annealing temperatures increased. The deconvolution technique of vibrational spectra allowed detection of small amounts of other forms accompanying the prevailing one.     

An algebraic axiomatization of the Ewald’s intuitionistic tense logic

Ewald (J Symbolic Logic 51(1):166–179, 1986) considered tense operators \(G\) , \(H\) , \(F\) and \(P\) on intuitionistic propositional calculus and constructed an intuitionistic tense logic system called IKt. The aim of this paper is to give an algebraic axiomatization of the IKt system. We will also show that the algebraic axiomatization given by Chajda (Cent Eur J Math 9(5):1185–1191, 2011) of the tense operators \(P\) and \(F\) in intuitionistic logic is not in accordance with the Halmos definition of existential quantifiers. In this paper, we will study the IKt variety of IKt-algebras. First, we will introduce some examples and we will prove some properties. Next, we will prove that the IKt system has IKt-algebras as algebraic counterpart. We will also describe a discrete duality for IKt-algebras bearing in mind the results indicated by Or?owska and Rewitzky (Fundam Inform 81(1–3):275–295, 2007) for Heyting algebras. We will also get a general construction of tense operators on a complete Heyting algebra, which is a power lattice via the so-called Heyting frame. Finally, we will introduce the notion of tense deductive system which allowed us both to determine the congruence lattice in an IKt-algebra and to characterize simple and subdirectly irreducible algebras of the IKt variety.     

On estimation and influence diagnostics for zero-inflated negative binomial regression models

The zero-inflated negative binomial model is used to account for overdispersion detected in data that are initially analyzed under the zero-inflated Poisson model. A frequentist analysis, a jackknife estimator and a non-parametric bootstrap for parameter estimation of zero-inflated negative binomial regression models are considered. In addition, an EM-type algorithm is developed for performing maximum likelihood estimation. Then, the appropriate matrices for assessing local influence on the parameter estimates under different perturbation schemes and some ways to perform global influence analysis are derived. In order to study departures from the error assumption as well as the presence of outliers, residual analysis based on the standardized Pearson residuals is discussed. The relevance of the approach is illustrated with a real data set, where it is shown that zero-inflated negative binomial regression models seems to fit the data better than the Poisson counterpart.     

Tuning of Cell–Biomaterial Anchorage for Tissue Regeneration

Which mechanisms mediate cell attachment to biomaterials? What role does the surface charge or wettability play on cell–material anchorage? What are the currently investigated strategies to modify cell–matrix adherence spatiotemporally? Considering the development of scaffolds made of biocompatible materials to temporarily replace the structure and/or function of the extracellular matrix, focus is given to the analysis of the specific (i.e., cell adhesive peptide sequences) and unspecific (i.e., surface charge, wettability) mechanisms mediating cell‐matrix interactions. Furthermore, because natural tissue regeneration is characterized by the dynamic attachment/detachment of different cell populations, the design of advanced scaffolds for tissue engineering, based in the spatiotemporal tuning of cell–matrix anchorage is discussed.     

Bioglass-based scaffolds incorporating polycaprolactone and chitosan coatings for controlled vancomycin delivery

Highly porous scaffolds have been fabricated by the replication technique using 45S5 Bioglass^® (BG) powder. For the purpose of imparting a local drug release capability, the scaffolds were coated with polycaprolactone and vancomycin-loaded chitosan by a two-step procedure. Bare BG scaffolds loaded with vancomycin via a direct immersion method were used as control. The chemical composition and microstructure of bare and coated scaffolds were characterized through Fourier-transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM), respectively. The mechanical properties of the coated scaffolds were significantly improved compared with uncoated scaffolds; the compressive strength values of the coated scaffolds were about 3 times and the area under the stress–strain curve was about 7 times higher than those of the uncoated scaffolds. The scaffolds degradation behavior and the drug release profiles were studied in a phosphate buffered saline (PBS) solution. There was a sharp release of the drug in the first few hours (8 h) for both bare and coated scaffolds. For the bare scaffolds the drug was released completely in 24 h. However, the coated scaffolds showed a sustained release in a period of 11 days, suggesting the potential of the present polymer coated BG scaffolds to be used as bone tissue scaffolds with drug carrier and delivery ability.     

Negative Cooperativity in NAD(P)H Quinone Oxidoreductase 1 (NQO1)

NAD(P)H quinone oxidoreductase-1 (NQO1) is a homodimeric protein that acts as a detoxifying enzyme or as a chaperone protein. Dicourmarol interacts with NQO1 at the NAD(P)H binding site and can both inhibit enzyme activity and modulate the interaction of NQO1 with other proteins. We show that the binding of dicoumarol and related compounds to NQO1 generates negative cooperativity between the monomers. This does not occur in the presence of the reducing cofactor, NAD(P)H, alone. Alteration of Gly150 (but not Gly149 or Gly174) abolished the dicoumarol-induced negative cooperativity. Analysis of the dynamics of NQO1 with the Gaussian network model indicates a high degree of collective motion by monomers and domains within NQO1. Ligand binding is predicted to alter NQO1 dynamics both proximal to the ligand binding site and remotely, close to the second binding site. Thus, drug-induced modulation of protein motion might contribute to the biological effects of putative inhibitors of NQO1.