Effective conductivity of heterogeneous multiphase media with circular inclusions

Determining the effective conductivity of heterogeneous media is a central problem in different fields of physics. The medium considered here contains cylinders (inclusions) of random conductivities that are distributed at random in an embedding matrix. For random systems, widely encountered in applications, we derive an approximative analytical solution that applies to significantly denser configurations than Maxwell first-order approximations. The analytic solution is tested against accurate numerical simulations. The widely used effective medium approach is shown to be exact for symmetric conductivity distributions and quite accurate for asymmetrical cases.     

Large transverse momentum particle production in αα and pp collisions at the CERN ISR

The production of charged hadrons with high p_T in αα collisions at √s=126 GeV and pp collisions at √s=31 and 63 GeV is compared, and the structure of the events associated with the high-pT particles is studied. The probability of finding associated particles close to the trigger particle increases strongly between √s=31 and 63 GeV for pp collisions. For p_T>2.5GeV/c the αα/pp cross section ratio at the same energy per nucleon is measured to be 18.7 ± 2.0, to be compared with A² = 16, and a higher associated multiplicity is observed for αα.     

E-beam radiation synthesis of xanthan-gum/carboxymethylcellulose superabsorbent hydrogels with incorporated graphene oxide

In this study the electron beam (e-beam) radiation synthesis in “paste-like condition” and characterization of the network structure of acrylic acid (AA) sodium salt/xanthan gum (XG)/carboxymethylcellulose (CMC) superabsorbent hydrogels incorporating graphene oxide (GO) was investigated. The effects of the AA concentration on gel fraction, sol-gel analysis, swelling degree and network parameters, as well as the relationship between these parameters and radiation dose was also established.

Gel fraction exceeds 90%, and the p₀/q₀ ratio shows a moderate degradation process. The swelling kinetic data were used to determine, first the swelling degree, second the diffusion characteristics, and third the average molecular weight between crosslinks (Mc), as well as. The diffusion data revealed a Fickian mechanism transport, for each hydrogel compositions. The network parameters (Mc and ξ) increased with absorbed dose, while cross-linking density and the radiation-chemical yields were decreased.     

Coordination Patterns of the Diphenyl-Phosphinodithioato Ligand in Tellurium Compounds

Abstract.

Solid state monomeric structures with monometallic biconnective (bidentate) diphenylphosphinodithioato groups were found in Ph₂Te(S₂PPh₂)₂ (1) or [Ph₃Te][S₂PPh₂] (2), while in the polymeric associations [Te₂(S₂PPh₂)₂]_n (3) and [PhTeS(S)PPh₂]_n (4) bimetallic biconnective (bridging) and monodentate biconnective (bridging) patterns were established by X-ray diffractometry. [Te(S₂PPh₂)₃]₂ (5) exhibits an unusual dimeric structure, with both monometallic biconnective and bimetallic triconnective ligand units.     

Synthesis and microbiological evaluation of several benzocaine derivatives

Starting from benzocaine, a well-known anaesthetic, ten derivatives were synthesized and characterized by UV–vis, IR, NMR, and elemental analysis. Most of the compounds contain residues with recognized biological activity, like nicotinic acid (vitamin B3 or PP), biotin (vitamin B7 or H), lipoic acid (thioctic acid), adamantine, as well as other residues of crown-ether type, benzofurazane, naphtylurea, di- and tri-nitrobenzene, and a nitroxide radical. The biological evaluation of the obtained compounds included hydrophobicity (lipophobicity) assay, total antioxidant and microbiological activity tests.     

Targeting Monoacylglycerol Lipase in Pursuit of Therapies for Neurological and Neurodegenerative Diseases

Neurological and neurodegenerative diseases are debilitating conditions, and frequently lack an effective treatment. Monoacylglycerol lipase (MAGL) is a key enzyme involved in the metabolism of 2-AG (2-arachidonoylglycerol), a neuroprotective endocannabinoid intimately linked to the generation of pro- and anti-inflammatory molecules. Consequently, synthesizing selective MAGL inhibitors has become a focus point in drug design and development. The purpose of this review was to summarize the diverse synthetic scaffolds of MAGL inhibitors concerning their potency, mechanisms of action and potential therapeutic applications, focusing on the results of studies published in the past five years. The main irreversible inhibitors identified were derivatives of hexafluoroisopropyl alcohol carbamates, glycol carbamates, azetidone triazole ureas and benzisothiazolinone, whereas the most promising reversible inhibitors were derivatives of salicylketoxime, piperidine, pyrrolidone and azetidinyl amides. We reviewed the results of in-depth chemical, mechanistic and computational studies on MAGL inhibitors, in addition to the results of in vitro findings concerning selectivity and potency of inhibitors, using the half maximal inhibitory concentration (IC₅₀) as an indicator of their effect on MAGL. Further, for highlighting the potential usefulness of highly selective and effective inhibitors, we examined the preclinical in vivo reports regarding the promising therapeutic applications of MAGL pharmacological inhibition.     

An Approximate Kinetic Treatment of Slow‐Initiated Living Polymerization. II. First‐Order Initiation and Half‐Order Propagation

An approximate analytical solution of the set of differential equations modeling the anionic polymerization of styrene is presented. By using this solution, a new method for calculating the initiation rate constant for this polymerization process was developed.     

Two phase photochemical synthesis of silver nanoparticles and their impact on the chlorophylls

Abstract

We have designed an experimental study dedicated to silver nanotoxicity using a suspension of citrate-silver nanoparticles, obtained by photochemical reduction. Fine granularity of generally symmetrical shape nanoparticles were evidenced by tansmission electron microscopy. The localized surface plasmon resonance spectral band revealed the intensification of silver nanoparticle formation under UV exposure. The nanotoxicity of silver nanoparticles was tested on cereal sprouts by measuring the concentrations of chlorophylls and carotenes in the green tissue. The differences between control samples, supplied with distilled water and test samples, loaded with different volumes of silver nanoparticles suspension were analyzed statistically, and compared with literature reports.     

Large amplitude oscillatory extension of soft polymeric networks

Using a filament stretching rheometer surrounded by a thermostatic chamber and equipped with a micrometric laser, it is possible to measure large amplitude oscillatory elongation (LAOE) on elastomeric based networks with no base flow as in the LAOE method for polymer melts. Poly(dimethylsiloxane)-based networks, considered as a model system for studying the development of soft elasticity, are mechanically characterised through reversed LAOE deformation, applying oscillatory measurements with several amplitudes and frequencies.