Aging-induced structural relaxation in cornstarch plasticized with urea and glycerol

In present work structural properties and aging of thermoplastic starches prepared by plasticization of cornstarch with urea, glycerol and their mixtures are studied using solid-state ¹H NMR and ¹³C NMR spectroscopy and WAXS measurements. Broad line ¹H NMR spectra reveal phase separation of plasticizers during aging of the samples with the same or higher relative amount of glycerol than the amount of urea. Glycerol in the TPS samples induces motion of starch chain segments, the mobility of which depends on the relative amount of glycerol. At the scale of nm, formation of B-type crystallites in the samples containing glycerol and also of single-helical crystallinity in all samples is observed during one-year aging through cross-polarization magic angle spinning ¹³C NMR spectra. Urea, when used as the sole plasticizer, prevents the ordering of starch chains in B-type crystallites. WAXS diffractograms show that regular crystals do not form in any of the samples.     

Editorial: Smart Solutions with Focus on Innovations from Various Perspectives

Mobile Networks and Applications -     

The role of salt abuse on risk for hypercalciuria

Background  

Elevated sodium excretion in urine resulting from excessive sodium intake can lead to hypercalciuria and contribute to the formation of urinary stones. The aim of this study was to evaluate salt intake in patients with urinary lithiasis and idiopathic hypercalciuria (IH).     

Calcium/chitosan spheres as catalyst for biodiesel production

Chitosan, an abundant biopolymer extracted from crustacean shells, can be used as a structuring agent by the insertion of calcium oxide and used as a catalyst in transesterification reactions. These calcium‐incorporated chitosan spheres were calcined in order to obtain a porous calcium catalyst without organic material. The materials were characterized using X‐ray diffraction, thermogravimetric analysis, Fourier transform infrared and X‐ray photoelectron spectroscopies, temperature‐programmed desorption of CO₂, scanning electron microscopy and specific surface area analysis. Afterwards the calcined calcium/chitosan spheres were used in the transesterification reaction of sunflower oil with methanol. The conversion of sunflower oil to methyl esters (Y_FAME), under optimized reaction conditions, which were determined by factorial experimental design (X_MR, 1:9; X_CAT, 3 wt%; time, 4 h; temperature, 60 °C; magnetic stirring, 1000 rpm), was 56.12 ± 0.32 wt%. These results show that chitosan can be used as a precursor for the formation of calcium/chitosan spheres, yielding a porous calcium oxide (with higher surface area) that can be used as an alkaline catalyst for biodiesel production. © 2014 Society of Chemical Industry     

Novel Antibacterial and Bioactive Silicate Glass Nanoparticles for Biomedical Applications

In this work, the authors propose a new quick sol–gel procedure for bioglass nanoparticles production containing 10% mol of silver (AgBGs). These new AgBGs are characterized by Zeta potential analysis, scanning electron microscopy with X‐ray microanalysis (SEM/EDS), X‐ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and microbiological tests to confirm their bioactive and antibacterial properties. SEM shows that the average particle size is less than 200 nm and EDS confirms the successful incorporation of Ag₂O in the bioglass matrix. XRD confirms the amorphous nature of the AgBGs and, after SBF immersion, reveals their bioactive behavior with the presence of crystalline phase of calcium silicate and phosphorus oxide, which are also detected by FTIR analysis. FTIR also confirms the formation of typical siloxane bonds resulting from the condensation of silicate glass. Lastly, it is found that the developed AgBGs has an antibacterial effect against two different types of bacteria, thus demonstrating their ability to reduce the bacterial infection within 16 h.

     

Orbital remote sensing of phytoplankton functional types: a new review

Phytoplankton functional types (PFTs) are groups of species that have specific roles in the biogeochemical cycles and trophic flow. These groups have been pointed out as keys to improve the knowledge on ecosystem dynamics and effects of climate and anthropogenic changes in the marine environment. Orbital remote sensing is stated as the only means capable of analysing spatio-temporal distribution of PFTs, over regional and global scales. Many research teams have focused their efforts on the development of PFT bio-optical models, presenting a great variety of approaches. Considerable advances have been achieved in a few years of research; however, challenges are still great. Further developments rely on improvements in the knowledge of PFTs' bio-optical characteristics and the possibility of integrating different bio-optical and ecological information. This article presents a new review of the state of the art of PFTs' characterization from space, with examples of the main models and a discussion of achievements, gaps and future perspectives.     

Potential Environmental Applications of Pure Zeolitic Material Synthesized from Fly Ash

A pure 4A∕X (60∕40) zeolite product was synthesized from silica extracts of the Meirama fly ash in northwestern Spain. A high cation-exchange capacity (4.7 meq∕g) was obtained for the zeolitic material. The potential application of this coal fly ash conversion product for decontamination of high heavy metal waters was evaluated using three high heavy metal waters from acid mine drainage around the pyrite Huelva belt. The results were compared with those obtained with an equivalent pure commercial synthetic zeolite. A considerable reduction in the heavy metal content was attained (Zn from 174 to <0.1 mg∕L, Cu from 36 to 0.1 mg∕L, Fe from 444 to 0.8 mg∕L, Mn from 74 to <0.1 mg∕L, Pb from 1.5 to <0.1 mg∕L, and Cd from 0.4 to <0.1 mg∕L), even in high Ca and Fe waters using zeolite doses from 5 to 30 mg∕L. Both precipitation and cation-exchange processes accounted for the reduction in the pollutant concentration in the treated waters. Leachable hazardous elements from coal fly ash, such as Mo, B, As, V, and Cr, were not fixed in the synthesis of pure zeolites from the silica extracts. Consequently, they did not restrict the potential applications of this material as an ion exchanger, unlike the zeolitic material obtained from fly ash by direct alkaline conversion.