Improving human health through understanding the complex structure of glucose polymers

Two highly branched glucose polymers with similar structures—starch and glycogen—have important relations to human health. Slowly digestible and resistant starches have desirable health benefits, including the prevention and alleviation of metabolic diseases and prevention of colon cancer. Glycogen is important in regulating the use of glucose in the body, and diabetic subjects have an anomaly in their glycogen structure compared with that in healthy subjects. This paper reviews the biosynthesis–structure–property relations of these polymers, showing that polymer characterization produces knowledge which can be useful in producing healthier foods and new drug targets aimed at improving glucose storage in diabetic patients. Examples include mathematical modeling to design starch with better nutritional values, the effects of amylose fine structures on starch digestibility, the structure of slowly digested starch collected from in vitro and in vivo digestion, and the mechanism of the formation of glycogen α particles from β particles in healthy subjects. A new method to overcome a current problem in the structural characterization of these polymers using field-flow fractionation is also given, through a technique to calibrate evaporative light scattering detection with starch.

Molecular Recognition of Aromatic Nitro Compounds at Cyclodextrin Dithiocarbamate-modified Electrodes

Silver electrodes were modified by the adsorption of α-, β-, and γ-cyclodextrin dithiocarbamates (2α–γ) and characterized by reductive desorption experiments. Their molecular recognition properties were studied by cyclic voltammetry using three families of positional isomers of aromatic nitro compounds. Electrodes modified with 2α and 2β were selective for meta and para isomers while 2γ showed little selectivity. These observations are explained in terms of cavity sizes and guest structure. Computational studies suggest that the main reason for the observed selectivity is the different position of the NO² group in ortho and para isomers with respect to the CD cavity.     

Ultrasound promoted synthesis of thioesters from 2-mercaptobenzoxa(thia)zoles

An ultrasound-enhanced method has been developed for the synthesis of a variety of thioesters from benzoyl chlorides and 2-mercaptobenzoxa(thia)zoles. Applying this methodology, 14 compounds were synthesized in excellent yields.     

Quantitative determination on heavy metals in different stages of wine production by Total Reflection X-ray Fluorescence and Energy Dispersive X-ray Fluorescence: Comparison on two vineyards

The purpose of this study is to determine the elemental content, namely heavy metals, of samples of vine-leaves, grapes must and wine. In order to assess the influence of the vineyard age on the elemental content throughout the several stages of wine production, elemental determinations of trace elements were made on products obtained from two vineyards aged 6 and 14 years from Douro region. The elemental content of vine-leaves and grapes was determined by Energy Dispersive X-Ray Fluorescence (EDXRF), while analysis of the must and wine was performed by Total Reflection X-ray Fluorescence (TXRF).     

Generalization of Selberg’s $$ \frac{3}{{16}} $$ theorem and affine sieve

An analogue of the well-known \frac316 \frac{3}{{16}} lower bound for the first eigenvalue of the Laplacian for a congruence hyperbolic surface is proven for a congruence tower associated with any non-elementary subgroup L of SL(2,Z). The proof in the case that the Hausdorff of the limit set of L is bigger than \frac12 \frac{1}{2} is based on a general result which allows one to transfer such bounds from a combinatorial version to this archimedian setting. In the case that delta is less than \frac12 \frac{1}{2} we formulate and prove a somewhat weaker version of this phenomenon in terms of poles of the corresponding dynamical zeta function. These “spectral gaps” are then applied to sieving problems on orbits of such groups.     

A branch-and-bound algorithm for hard multiple knapsack problems

The multiple knapsack problem (MKP) is a classical combinatorial optimization problem. A recent algorithm for some classes of the MKP is bin-completion, a bin-oriented, branch-and-bound algorithm. In this paper, we propose path-symmetry and path-dominance criteria for pruning nodes in the MKP branch-and-bound search space. In addition, we integrate the ??bound-and-bound?? upper bound validation technique used in previous MKP solvers. We show experimentally that our new MKP solver, which successfully integrates dominance based pruning, symmetry breaking, and bound-and-bound, significantly outperforms previous solvers on some classes of hard problem instances.