Jammed systems in slow flow need a new statistical mechanics

The slow dynamics of granular flow is studied as an extension of static granular problems, which, as a consequence of shaking or related regimes, can be studied by the methods of statistical mechanics. For packed (i.e. 'jammed'), hard and rough objects, kinetic energy is a minor and ignorable quantity, as is strain. Hence, in the static case, the stress equations need supplementing by 'missing equations' depending solely on configurations. These are in the literature; this paper extends the equilibrium studies to slow dynamics, claiming that the strain rate (which is a consequence of flow, not of elastic strain) takes the place of stress, and as before, the analogue of Stokes's equation has to be supplemented by new 'missing equations' which are derived and which depend only on configurations.     

Treatment Response to SGLT2 Inhibitors: From Clinical Characteristics to Genetic Variations

SGLT2 (sodium-glucose cotransporter 2) inhibitors are a new class of antihyperglycaemic drugs that act on the proximal tubules of the kidney. They have shown efficacy in the management of diabetes mellitus type 2 and their cardiovascular and renal safety have been extensively investigated and confirmed in clinical trials. However, inter-individual differences in response to treatment with SGLT2 inhibitors may present in everyday clinical practice, and good predictors of glycemic response and the risk for adverse events in an individual patient are lacking. As genetic variability of SGLT2 may influence the treatment response, pharmacogenetic information could support the choice of the most beneficial treatment strategy in an individual patient. This review focuses on the clinical and genetic factors that may influence the treatment response to SGLT2 inhibitors in type 2 diabetes patients with comorbid conditions.     

Studies on the Mechanical,Electrical Properties and Interaction of Petroleum Fuels with SBR/ Manganous Tungstate Nanocomposites

A novel nanocomposite based on styrene butadiene rubber (SBR) and manganous tungstate (MnWO₄) nanoparticles was prepared by a simple and inexpensive open two-roll mixing mill. The interaction of the nanoparticles with SBR matrix was studied by different characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and electrical properties. The effect of loading of MnWO₄ nanoparticles on the processing characteristics of mixed rubber compounds, mechanical properties and the transport properties of nanocomposites through petroleum fuels were also analysed. XRD of nanocomposite revealed that the addition of nanoparticles imparts a semi-crystalline or regular arrangement of chains in the composite. SEM analysis showed good dispersion of nanoparticles in the polymer matrix. Also it has been observed that the dispersion of nanoparticles decreases with increase in its loading. TGA analysis indicated better thermal stability of all nanocomposite and thermal stability increases with the loading of the nanoparticles. The AC conductivity and dielectric properties were greatly enhanced in the whole range of frequencies studied. The processing properties of rubber compounds like cure and scorch time decreases with increase in concentration of MnWO₄ nanoparticles and the maximum enhancement in torque was observed for 10 phr loading. The tensile strength, modulus, tear resistance, hardness and heat build-up of the composite increased whereas the resilience, compression set and elongation at break decreased with the loading of nanoparticles. Solvent penetration studies of nanocomposites were done in petroleum fuels at different temperatures.The solvent uptake was the minimum for composite with 10 phr of MnWO₄ and penetration of solvent increased with further addition of nanoparticles.     

Nanocomposite materials based on zinc sulfide nanoparticles reinforced chlorinated styrene butadiene rubber

The effect of zinc sulfide (ZnS) nanoparticles in chlorinated styrene‐butadiene rubber (Cl‐SBR) was analyzed by X‐ray diffraction analysis (XRD), scanning electron microscopy (SEM), Differential Scanning Calorimetry, and impedance analyzer. The cure time, mechanical properties, and solvent transport of petroleum fuels through the Cl‐SBR/ZnS nanocomposites at different temperatures were evaluated. XRD and SEM studies showed that ZnS nanoparticles were well‐placed in the polymeric structure of Cl‐SBR. The increased glass transition temperature of the composite with the loading of nanoparticles indicated the increased molecular rigidity. Rheometric torque, alternating current conductivity, dielectric property, tensile strength, tear resistance, modulus, hardness, abrasion resistance, heat build‐up, and compression set were increased with the loading of nanoparticles, however, cure and scorch time, elongation at break, and resilience were reduced with the loading of nanoparticles. The diffusion results have been explained in terms of the size of liquid molecules and the diffusion mechanism was found to follow the anomalous trend. The activation energy for diffusion, sorption and permeation process was evaluated. These activation energy parameters were increased with the size of the penetrant molecules and also with the loading of nanoparticles. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46538.     

Determination of the geographical origin of Slovenian black locust,lime and chestnut honey

The geographical origin of three Slovenian unifloral honey types (black locust, lime and chestnut) was investigated by analysis of some physico-chemical parameters, the elemental content using total reflection X-ray fluorescence spectrometry (TXRF) and the stable carbon and nitrogen isotope ratios using isotope ratio mass spectrometry (IRMS). The results were interpreted by chemometric methods. A total of 122 samples of Slovenian black locust, lime and chestnut honeys were collected from domestic beekeepers all over Slovenia for three years. Slovenia is a small country by area, but paedologically and climatically diverse, therefore offering interesting possibilities for studying geographical influences. The combination of the investigated parameters offers the possibility of distinguishing among samples of specific honey types from the four different Slovenian natural-geographical macroregions, namely the Alpine, Dinaric, Pannonnian and Mediterranean regions. Lime honey samples were 100% correctly classified, while the success rates for black locust and chestnut honeys were slightly lower at 98.2% and 94.6%, respectively.     

Evaluation and improvement of antioxidant and antibacterial activities of supercritical extracts from clove buds

For the first time, extracts from clove buds obtained by supercritical carbon dioxide extraction were screened for antioxidant and antibacterial activities. Additionally, antioxidant and antibacterial activities of extracts obtained by the supercritical extraction of the clove bud–oregano leaf mixtures were studied. Supercritical extract of pure clove had the highest eugenol (64%) and total phenolic content (530.56 mg GAE/g_extract). All extracts had antioxidant activity comparable to synthetic antioxidants against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and formation of peroxides. Presence of 0.6% and 5% of oregano extract in the clove extracts obtained from the clove–oregano plant mixtures improved their antioxidant activity with respect to the extract from pure clove. Clove extract showed moderate antibacterial activities against selected Staphylococcus and Enterococcus bacterial strains. Presence of 50% of the oregano extract improved antibacterial activity of clove extract against all tested strains and resulted in a synergistic antibacterial activity against Methicillin-resistant Staphylococcus haemolyticus strain (MIC ? 1.25 μg/mL). Study demonstrated great potential of supercritical clove extract as natural functional ingredient and the possibility of increasing its antioxidant and antibacterial efficiencies in order to apply lower concentrations and to reduce undesirable flavour notes and toxicological effects in final products.     

DSC study of the cure kinetics during nanocomposite formation: Epoxy/poly(oxypropylene) diamine/organically modified montmorillonite system

The effect of an organically modified montmorillonite (OMMT) on the curing kinetics of a thermoset system based on a bisphenol A epoxy resin and a poly(oxypropylene)diamine curing agent were studied by means of differential scanning calorimetry (DSC) in isothermal and dynamic (constant heating rate) conditions. Montmorillonite and prepared composites were characterized by X‐ray diffraction analysis (XRD) and simultaneous differential scanning calorimetry–thermogravimetric analysis (DSC–TGA). Analysis of DSC data indicated that the presence of the filler has a very small effect on the kinetics of cure. A kinetic model, arising from an autocatalyzed reaction mechanism, was applied to the DSC data. Fairly good agreement between experimental and modeling data was obtained. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 550–557, 2006     

Valorisation of phenolic composition,antioxidant and cell growth activities of tomato waste

Tomato waste, a by-product in juice processing, obtained from different tomato genotypes, was subjected to evaluation as potential source of phenolic antioxidants and anticancer agents. Some individual phenolic compounds, including phenolic acids and flavonoids, were identified and quantified by HPLC. The antioxidant activity of tomato waste extracts was tested by measuring their ability to scavenge hydroxyl and superoxide anion radicals by ESR spectroscopy. The highest hydroxyl radical scavenging activity (IC₅₀ = 0.03 mg/ml) was obtained in the case of Novosadski niski waste extract. The Rutgers waste extract showed the best performance in scavenging superoxide anion radicals (IC₅₀ = 0.45 mg/ml). Cell growth effects were determined in HeLa, MCF7 and MRC-5 cell lines by SRB test. In all cell lines antiproliferative effects were observed at higher investigated concentrations (?6.3 mg/ml). The strongest activity against cancer cells was observed by Saint Pierre extract in HeLa cell line (IC₅₀ = 13.7 mg/ml).