Determination of Required HLB of Capryol 90

The required hydrophilic-lipophilic balance (HLB) of an oily substance indicates the HLB of the surfactants required to prepare a stable emulsion using the oil. This study utilizes empirical method to calculate required HLB (RHLB) of Capryol 90 using surfactant blends (Span 20, Tween 20, vitamin E TPGS, Pluronic F68, Span 60, and Tween 80). The methods used were assessment of degree of creaming after centrifugation and after shelf storage for 28 days at room temperature, turbidimetric method, accelerated stability study, and droplet size analysis. The droplet size was found to be in the range of 15 to 2 µm and v/v% separation after centrifugation was found to be 0–82%. The RHLB for Capryol 90 was found to be 15. The effect of various surfactant blends was investigated. Results revealed that a blend of tocopherol polyethylene glycol succinate (TPGS) and Pluronic F68 gave the most stable emulsion for Capryol 90.     

1H NMR studies of binary and ternary dapsone supramolecular complexes with different drug carriers: EPC liposome,SBE‐β‐CD and β‐CD

Binary and ternary systems composed of dapsone, sulfobutylether‐β‐cyclodextrin (SBE‐β‐CD), β‐CD and egg phosphatidylcholine (EPC) were evaluated using 1D ROESY, saturation transfer difference NMR and diffusion experiments (DOSY) revealing the binary complexes Dap/β‐CD (K_a 1396 l mol^?1), Dap/SBE‐β‐CD (K_a 246 l mol^?1), Dap/EPC (K_a 84 l mol^?1) and the ternary complex Dap/β‐CD/EPC (K_a 18 l mol^?1) in which dapsone is more soluble. Copyright © 2014 John Wiley & Sons, Ltd.     

Evidences of macromolecular chains confinement of ethylene–propylene copolymer in organophilic montmorillonite nanocomposites

A random ethylene–propylene copolymer (EPM) functionalized with grafted diethylsuccinate groups was melt blended with increasing amount (to 20 wt%) of organophilic montmorillonite (OMMT) to prepare nanocomposites with different morphologies as evidenced by XRD and TEM analysis. All the nanocomposites were treated with boiling toluene that did not extract a significant amount of EPM. The increase of not-extracted EPM with the increasing quantity of OMMT suggested strong interactions of the polymer chains with the inorganic substrate. The DSC measurements of nanocomposites and the corresponding insoluble residues revealed a higher T_g values with larger amount of inorganic particles. The dielectric relaxation analysis confirmed the evidence of strong interactions among montmorillonite and the polar diethylsuccinate groups for the macromolecules trapped due to the presence of the inorganic layers. The results were discussed with reference to their relevance as an evidence of nanoconfinement at polymer clay interface and correlated with the clay basal distance variation due to the intercalation process.     

Compositional and technological features of glazed pottery from Aosta Valley (Italy): a SEM–EDS investigation

Twelve finds from archaeological excavations carried out in the Aosta region (Italy) were studied by scanning electron microscopy coupled with energy-dispersive X-ray detection (SEM–EDS). The archaeological samples were shards of glazed pottery dating from the fourth to the seventh century AD. Analysis of ceramic bodies revealed a general homogeneity in composition among the studied samples and the use of a noncalcareous clay for their manufacture; however, two shards stand out due to their high iron contents. Glazes proved to be high-lead products with more than 70% PbO in all of the samples investigated but one. For the latter, a composition poorer in lead and richer in silicon, aluminium and iron was found. SEM observation of the contact region between body and glaze suggests that the vitreous coatings were mostly obtained by applying the glazing components onto the unfired clay body; moreover, a comparison between clay and glaze compositions suggests the use of a lead compound mixed with a silica-rich material, not a lead compound by itself.     

Effect of concentrate solution pH and mineral composition of a whey protein diluate solution on membrane fouling formation during conventional electrodialysis

The aim of this work was to study the effect of the concentrate solution pH and the composition in calcium, carbonate and protein of the diluate solution to be treated by conventional electrodialysis on the fouling of ion-exchange membranes. Conductivity, system resistance, pH of the diluate and cation migration were monitored to follow the evolution of the demineralization. Total cation migration was similar for all conditions although different forms of fouling were identified after three consecutive 100 min electrodialysis treatments. The nature of fouling and the membrane surface fouled depended on the concentrate pH value, the diluate mineral composition and the intrinsic composition of the whey isolate. Once conditions leading to membrane fouling were identified, an alternative configuration for our electrodialysis stack is proposed to prevent fouling onset.     

Lithiation and electrophilic substitution of 8-chlorodibenz[b,f][1,4]-oxazepine-10-tert-butylcarbamate: The preparation of novel fused heterocyclic derivatives of 8-chlorodibenzoxazepine

Lithiation of 8-chlorodibenz[b,f][1,4]oxazepine-10-tert-butylcarbamate ( 1 ) is described. Electrophilic substitution of the resulting N-Boc dibenzoxazepine α- lithioamine 2 with ketones, aldehydes, nitriles, iso-cyanates and imines, followed by an in-situ cyclization, gave fused carbamates 5–26 , fused 2H-imidazol-2-ones 27–29 , fused hydantoins 30–32 , and fused ureas 33–35 , respectively, in 11–66% yield.     

Metal-free direct arylations of indoles and pyrroles with diaryliodonium salts

Direct arylations of indoles and pyrroles with differently substituted diaryliodonium salts were shown to efficiently proceed in the absence of metal catalysts.     

Can human prolidase enzyme use different metals for full catalytic activity?

The catalytic hydrolysis of the Gly-Pro substrate by the bimetallic prolidase active site model cluster has been investigated at the DF/B3LYP level of theory, in order to provide fundamental insights into the still poorly understood mechanism of prolidase catalysis. To date, the majority of prolidases exhibits metal-dependent activity, requiring two divalent cations such as Zn(2+), Mn(2+), or Co(2+) for maximal activity. In addition, it has been shown recently that two different metal ions in the active site of human prolidase (Zn and Mn) can coexist, with the protein remaining partially active. With the purpose of identifying which is the most efficient dimetallic center for the prolidase catalyzed reaction, Zn(II), Co(II), and Mn(II) have been examined as potential catalytic metals for this enzyme. Furthermore, to better elucidate the exact roles played by the metals occupying the site 1 and site 2 positions, the hetero-bimetallic active site having Zn and Mn cations has been also investigated, considering the two derivatives Mn1-Zn2 and Zn1-Mn2. The rate-determining step of the hydrolysis reaction is always found to be the nucleophilic addition of the hydroxide ion on the carbonyl carbon of the scissile peptide bond, followed by the less energetically demanding proline-peptide C-N bond scission. The analysis of the involved energy barriers does not indicate clearly a preference for a particular metal by the prolidase enzyme. Instead, we may point out a slightly better behavior of the cobalt-containing cluster as far as both tetrahedral formation and its decomposition are concerned, due to a greater degree of ligands-to-metals charge transfer. The mixed Mn-Zn hetero-dimetallic clusters appear to be also able to perform the hydrolysis of the Pro-Gly substrate, with a slight preference for the Mn1-Zn2 configuration.     

Quantitative impact of small angle forward scatter on whole blood oximetry using a Beer-Lambert absorbance model

It is well known that red blood cell scattering has an impact on whole blood oximetry as well as in vivo retinal oxygen saturation measurements. The goal of this study was to quantify the impact of small angle forward scatter on whole blood oximetry for scattering angles found in retinal oximetry light paths. Transmittance spectra of whole blood were measured in two different experimental setups: one that included small angle scatter in the transmitted signal and one that measured the transmitted signal only, at absorbance path lengths of 25, 50, 100, 250 and 500 μm. Oxygen saturation was determined by multiple linear regression in the 520-600 nm wavelength range and compared between path lengths and experimental setups. Mean calculated oxygen saturation differences between setups were greater than 10% at every absorbance path length. The deviations to the Beer-Lambert absorbance model had different spectral dependences between experimental setups, with the highest deviations found in the 520-540 nm range when scatter was added to the transmitted signal. These results are consistent with other models of forward scatter that predict different spectral dependences of the red blood cell scattering cross-section and haemoglobin extinction coefficients in this wavelength range.