Large Communities in a Scale-Free Network

We prove the existence of a large complete subgraph w.h.p. in a preferential attachment random graph process with an edge-step. That is, we consider a dynamic stochastic process for constructing a graph in which at each step we independently decide, with probability \(p\in (0,1)\), whether the graph receives a new vertex or a new edge between existing vertices. The connections are then made according to a preferential attachment rule. We prove that the random graph \(G_{t}\) produced by this so-called generalized linear preferential (GLP) model at time t contains a complete subgraph whose vertex set cardinality is given by \(t^\alpha \), where \(\alpha = (1-\varepsilon )\frac{1-p}{2-p}\), for any small \(\varepsilon >0\) asymptotically almost surely.     

Benzyl­triethyl­ammonium 2,2,2,4‐tetra­chloro‐2,5‐di­hydro‐1,2λ5‐oxatellurole

The geometry around the Te atom in the anion in C₁₃H₂₂N⁺·C₃H₃Cl₄OTe^? is distorted pseudo‐octahedral with three Cl atoms and the O atom forming the equatorial plane, and the C atom lying opposite the tellurium lone pair. Distances and angles are: Te—O 2.0120 (18), Te—C 2.072 (2), Te—Cl 2.5239 (7), 2.5283 (7) and 2.5577 (7) Å; O—Te—C 81.61 (9), O—Te—Cl 90.69 (6), 90.99 (6) and 168.13 (5), C—Te—Cl 87.13 (8), 86.64 (8) and 86.59 (8), and Cl—Te—Cl 87.02 (2), 90.00 (3) and 173.24 (3)°. The anions are arranged in an infinite zigzag chain parallel to the a axis through a secondary Te?Cl bond [3.8391 (8) Å].     

Microencapsulated and Lyophilized Propolis Co-Product Extract as Antioxidant Synthetic Replacer on Traditional Brazilian Starch Biscuit

The residue from commercial propolis extraction may have significant antioxidant power in food technology. However, among the challenges for using the propolis co-product as an inhibitor of lipid oxidation (LO) in baked goods is maintaining its bioactive compounds. Therefore, this study aimed to determine the propolis co-product extracts’ capability to reduce LO in starch biscuit formulated with canola oil and stored for 45 days at 25 °C. Two co-product extracts were prepared: microencapsulated propolis co-product (MECP) (with maltodextrin) and lyophilized propolis co-product (LFCP), which were subjected to analysis of their total phenolic content and antioxidant activity (AA). Relevant antioxidant activity was observed using the methods of analysis employed. The spray-drying microencapsulation process showed an efficiency of 63%. The LO in the biscuits was determined by the thiobarbituric acid reactive substances (TBARS) test and fatty acid composition by gas chromatography analysis. Palmitic, stearic, oleic, linoelaidic, linoleic, and α-linolenic acids were found in biscuits at constant concentrations throughout the storage period. In addition, there was a reduction in malondialdehyde values with the addition of both propolis co-product extracts. Therefore, the propolis co-product extracts could be utilized as a natural antioxidant to reduce lipid oxidation in fatty starch biscuit.     

Modulating Glycoside Hydrolase Activity between Hydrolysis and Transfer Reactions Using an Evolutionary Approach

The proteins within the CAZy glycoside hydrolase family GH13 catalyze the hydrolysis of polysaccharides such as glycogen and starch. Many of these enzymes also perform transglycosylation in various degrees, ranging from secondary to predominant reactions. Identifying structural determinants associated with GH13 family reaction specificity is key to modifying and designing enzymes with increased specificity towards individual reactions for further applications in industrial, chemical, or biomedical fields. This work proposes a computational approach for decoding the determinant structural composition defining the reaction specificity. This method is based on the conservation of coevolving residues in spatial contacts associated with reaction specificity. To evaluate the algorithm, mutants of α-amylase (TmAmyA) and glucanotransferase (TmGTase) from Thermotoga maritima were constructed to modify the reaction specificity. The K98P/D99A/H222Q variant from TmAmyA doubled the transglycosydation/hydrolysis (T/H) ratio while the M279N variant from TmGTase increased the hydrolysis/transglycosidation ratio five-fold. Molecular dynamic simulations of the variants indicated changes in flexibility that can account for the modified T/H ratio. An essential contribution of the presented computational approach is its capacity to identify residues outside of the active center that affect the reaction specificity.     

Measuring velocity of speckle fields with digital speckle pattern interferometry

We investigate a digital method for detecting the velocity of a diffusing object. The technique is based on Digital Speckle Pattern Interferometry (DSPI). A set of reference fringes is generated externally through the reference beam in a digital interferometer. As the object moves, subsequent frames are acquired and subtracted according to the normal DSPI procedure and stored. By means of the theory of first order speckle statistics applied to speckle intensity correlation, we relate the visibility variations in the reference fringes with the object velocity. Thus, by measuring the fringe visibility variation in the resulting DSPI stored frames the mean object velocity can be obtained. The theoretical results are experimentally verified.     

Study of the influence of plasticizers on the thermal and mechanical properties of poly(3-hydroxybutyrate) compounds

The influence of four types of plasticizers, dioctyl phthalate (DOP), dioctyl adipate (DOA), triacetyl glycerol (TAG) and polyadipate (PA), in the thermal and mechanical properties of Poly(3-hydroxybutyrate) (PHB), a highly crystalline biodegradable polyester, was evaluated in this work. The plasticizers were introduced alone or mixtures of them, using concentrations that varied from 5 to 30% wt. Their influence in some important polymer parameters as Tg, Tm and degree of crystallinity, and on its mechanical behavior, elongation and tensile strain were investigated. The best results were obtained for the sample with 30% TAG and that one using a binary mixture of plasticizers PA 20% and TAG 10%.     

Mixture-Based Probabilistic Graphical Models for the Label Ranking Problem

The goal of the Label Ranking (LR) problem is to learn preference models that predict the preferred ranking of class labels for a given unlabeled instance. Different well-known machine learning algorithms have been adapted to deal with the LR problem. In particular, fine-tuned instance-based algorithms (e.g., k-nearest neighbors) and model-based algorithms (e.g., decision trees) have performed remarkably well in tackling the LR problem. Probabilistic Graphical Models (PGMs, e.g., Bayesian networks) have not been considered to deal with this problem because of the difficulty of modeling permutations in that framework. In this paper, we propose a Hidden Naive Bayes classifier (HNB) to cope with the LR problem. By introducing a hidden variable, we can design a hybrid Bayesian network in which several types of distributions can be combined: multinomial for discrete variables, Gaussian for numerical variables, and Mallows for permutations. We consider two kinds of probabilistic models: one based on a Naive Bayes graphical structure (where only univariate probability distributions are estimated for each state of the hidden variable) and another where we allow interactions among the predictive attributes (using a multivariate Gaussian distribution for the parameter estimation). The experimental evaluation shows that our proposals are competitive with the start-of-the-art algorithms in both accuracy and in CPU time requirements.     

Changes in the spectroelectrochemical properties of copper(II) hexacyanoferrate(III) during electrochemical insertion of alkaline ions

Journal of Solid State Electrochemistry - In this work, the influence of the electrochemical insertion of different alkali ions, e.g., lithium, sodium, and potassium, on the electrochromic...