The steryl ester and phospholipid fatty acids of the spongeAgelas conifera from the Colombian Caribbean

The steryl ester and phospholipid fractions of the marine spongeAgelas conifera were isolated and analyzed. The fatty acyl components of the steryl ester and phospholipid fractions as determined by gas chromatography and gas chromatography/mass spectrometry were very similar and consisted of 56.8 and 62.7% of C₁₄−C₂₀ acids (normal; branched, especiallyiso andanteiso; and monounsaturated, particularly Δ⁹ and Δ¹¹ acids) and of 43.1 and 35.5% of C₂₄−C₂₆ acids (Δ^5,9 diunsaturated acids), respectively. The major constituent fatty acids detected were 13-methyltetradecanoic,n-hexadecanoic, 10-methylhexadecanoic, 11-octadecenoic, 12-methyloctadecanoic, 5,9-pentacosadienoic and 5,9-hexacosadienoic acids. The phospholipids isolated were identified as phosphatidylcholine (37%), phosphatidylserine (34%), phosphatidylethanolamine (16%) and phosphatidylinositol (11%). The distribution of fatty acids within the phospholipid classes was also determined.     

Fullerene C₆₀ as a multifunctional system for drug and gene delivery

The fullerene family, and especially C(60), has delighted the scientific community during the last 25 years with perspective applications in a wide variety of fields, including the biological and the biomedical domains. Several biomedical uses have been explored using water-soluble C(60)-derivatives. However, the employment of fullerenes for drug delivery is still at an early stage of development. The design and synthesis of multifunctionalized and multimodal C(60) systems able to cross the cell membranes and efficiently deliver active molecules is an attracting challenge that involves multidisciplinary strategies. Promising results have emerged in the last years, bringing fullerenes again to the front of interest. Herein, the state of the art of this emerging field is presented and illustrated with some of the most representative examples.     

Phase and Rheological Behavior of Cetyldimethylbenzylammonium Salicylate (CDBAS) and Water

The temperature–composition phase diagram in the diluted region of the cationic surfactant cetyldimethylbenzylammonium salicylate/water system was studied with a battery of techniques. The Krafft temperature (T _k = 33 ± 1 °C) was measured by differential scanning calorimetry, polarizing microscopy, conductimetry, viscosimetry, and rheometry. The critical vesicle concentration (cvc, ~0.002 wt%) and a vesicle–micellar transition (cvm, ~0.005 wt%) was detected at a temperature of 35 °C. Below T _k and concentrations ≤2 wt%, a transparent solution is formed (I). Above 2–8.5 wt%, a lamellar (L₁) phase forms. At higher concentrations and up to 12 wt%, a second lamellar phase (L₂) is detected. From 12.4 to 15.5 wt%, an emulsion phase (E) is formed. Rheological dynamic measurements for the I phase indicate that the system exhibits a predominantly viscous behavior (G′ < G″) for concentrations lower than the overlap or entanglement concentration (C _e, ~0.75 wt%). At higher concentrations, wormlike micelles form and the elastic behavior predominates (G′ > G″). The elastic (G′) modulus collapses in a concentration–time master curve in the whole reduced frequencies range ωτ _c examined, whereas the viscous modulus (G″) collapses only at reduced frequencies lower than 0.1. Reduced stress plotted as a function of the reduced shear rate yields a good superposition of the curves at the different concentrations up to the onset of the non-linear behavior.     

Mechanical properties of carbon nanofiber/fiber-reinforced hierarchical polymer composites manufactured with multiscale-reinforcement fabrics

Hierarchical polymer composites – defined as carbon nanofiber/fiber-reinforced polymer composites – were manufactured using multiscale-reinforcement fabrics (MRFs) and they were characterized for their mechanical properties. The MRFs were fabricated by electrophoretic deposition of carboxylic acid- or amine-functionalized carbon nanofibers (CNFs) on the surface of sized or unsized carbon fiber layers. Compared to the base composite (not containing CNFs), the hierarchical composites containing the functionalized CNFs showed an increase in interlaminar shear strength (ILSS) and compressive strength. Panels containing amine-functionalized CNFs had the highest increase in properties: 12% in ILSS and 13% in compressive strength. The reinforcement mechanism was also investigated with emphasis placed on the fiber/matrix interface and the load transfer between matrix, CNFs, and carbon fiber.     

Oxygen migration on the graphene surface. 2. Thermochemistry of basal-plane diffusion (hopping)

Thermodynamic affinities, activation energies and diffusion coefficients for oxygen mobility on the graphene surface are calculated using density functional theory (DFT). We report and discuss the effects of geometry, charge distribution and heteroatom substitution on the migration of epoxy oxygen on the basal plane: both the driving force and the ease of surface hopping are very sensitive to their variations. A significant decrease in the hopping energy barrier is observed when graphene contains free edge sites and oxygen functionalities, as well as upon an increase in electron density; conversely, the barrier increases as a consequence of electron removal, and the propensity for graphene ‘unzipping’ also increases. There is a correlation between the hopping barrier and the C–O bond strength of the leaving epoxide group. Under the most favorable conditions investigated, oxygen mobility is quite high, of the same order as that of gas-phase O₂ in micropores (ca. 10⁻⁹ m²/s). This is consistent with the increasingly acknowledged role of basal-plane oxygen as a protagonist (e.g., reaction intermediate), instead of a spectator, in the wide variety of adsorption and reaction processes involving sp²-hybridized carbon materials.     

Fast and efficient synthesis of high molecular weight poly(epsilon‐caprolactone) diols by microwave‐assisted polymer synthesis

Because of advantageous features such as shorter reaction times, greater yields, limited generation of by‐products and relatively easy and straightforward scale‐up, microwave‐assisted synthesis has become a very appealing tool in organic synthesis. Conversely, its implementation in the context of the synthesis of biomaterials for biopharmaceutical applications has been more limited. The present work reports on the fast and efficient microwave‐assisted synthesis of poly(ethylene glycol) (PEG)‐initiated poly(ε‐caprolactone) diols (PCL) by the ring‐opening polymerization (ROP) of ε‐caprolactone using stannous octanoate as catalyst. Since the PEG content in the synthesized copolymers was extremely low (0.2–1.9%), products were highly hydrophobic and displayed the intrinsic thermal properties of pure PCL. As opposed to the more time‐consuming conventional thermally‐driven synthesis that usually demands 2–3 h, the microwave technique resulted in intermediate to high molecular weight PEG‐PCL derivatives within 10–15 min. The influence of different parameters affecting the synthetic process, namely monomer‐to‐initiator ratio, reaction time, catalyst concentration and the presence, type, and concentration of solvent were thoroughly investigated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Purity,quality and stability of Argentinean virgin olive oils

In this paper we evaluate the stability, purity and regulated quality composition of fatty acids and sterols (both physico‐chemical and sensory) of commercial Argentinean virgin olive oils in order to evaluate their acceptance on the world market. For this purpose, samples of the best known and most widely distributed oils in supermarkets located in Buenos Aires (Argentina) were acquired. After thoroughly analysing these samples, only 20% were considered to have an acceptable quality. However, some were excluded because of their high campesterol content, which could be an intrinsic characteristic of these oils. The most useful analytical parameter used to confirm authenticity was ECN‐42 R – ECN‐42 T, followed by wax content and 3.5 stigmastadienes. Only 24% of the extra‐virgin olive oil samples were classified as ‘extra‐virgin’ from the regulated quality viewpoint. The low oleic and high linolenic acid contents of the Argentinean virgin olive oils stand out when compared with European virgin olive oils. The oxidative stability values may be considered very low, indeed even lower than those obtained in Spanish virgin olive oils.     

Melt processing of ethylene–vinyl acetate/banana starch/Cloisite 20A organoclay nanocomposite films: structural,thermal and composting behavior

This work shows the preparation of ethylene vinyl acetate copolymer/banana starch/Cloisite 20A organoclay (EVA/starch/C20A) nanocomposites by melt processing. Wide angle X-ray diffraction (WAXD), field emission scanning electron microscopy (FE-SEM), differential scanning calorimetry and thermogravimetric analysis were used to characterize the obtained nanocomposites. Mechanical properties were also determined. In addition, the performance of the nanocomposite films under composting was preliminarily studied; it was conducted using the soil burial test method. Despite knowing that the starch is difficult to process by extrusion, nanocomposite films with high homogeneity were obtained. In this case, C20A organoclay acts as an effective surfactant to make the starch natural polymer compatible with the EVA synthetic polymer. The good compatibility between EVA, starch and C20A clay was also deduced by the formation of intercalated and intercalated-exfoliated structures determined by WAXD and FE-SEM. Physical evidence of the damage in EVA/starch/C20A nanocomposite films after the composting test was observed. It is worth noting that despite the absence of starch, the EVA/C20A nanocomposite film, used as a control, also showed surface damage. This behavior is related to the organic modifier linked to clay C20A, which contains molecules derived from fatty acids that can be used as a food source for microorganisms.

     

Random Copolymers with 2,2′-Dioxy-1,1′-biphenyl-phosphazene and Chiral 2,2′-dioxy-1,1′-binaphthylphosphazene Units Functionalized in the 6,6′-Positions with PPh<Subscript>2</Subscript> Groups as Precursors for Ru(arene) Catalysts

The chiral phosphazene copolymers {[NP(O₂C₁₂H₈)]_0.9[NP(O₂C₂₀H₁₂)]_0.1} (1) and {[NP(O₂C₁₂H₈)]_0.9[NP(O₂C₂₀H₁₀Br₂)]_0.1} _n (2) [(O₂C₁₂H₈) = 2,2′-dioxy-1,1′-biphenyl; (O₂C₂₀H₁₂) = R-2,2′-dioxy-1,1′-binaphthyl and (O₂C₂₀H₁₀Br₂) = R-6,6′-dibromo-2,2′-dioxy-1,1′-binaphthyl] were prepared by sequential substitution from [NPCl₂] _n and the corresponding dihydroxy-biphenyl or binaphthyl reagents in the presence of Cs₂CO₃ and K₂CO₃. The reaction of (2) with ^tBuLi in THF, followed by addition of PPh₂Cl and a treatment with SiHCl₃/PPh₃ to eliminate any oxidized OC₆H₄P(O)Ph₂ groups, gave the phosphine containing copolymer {[NP(O₂C₁₂H₈)]_0.9[NP(O₂C₂₀H₁₀[PPh₂]₂)]_0.1} _n (3), that was used as a chiral ligand to support [Ru(p-cymene)Cl] complexes. The resulting catalyst was active for hydrogen transfer from isopropyl alcohol to acetophenone but the placement of the Ru centers in the 6,6′-positions of the binaphthoxyphosphazene units induced no enantioselectivity. Dedicated to Professor Christopher Allen.     

Expression of DDX11 and DNM1L at the 12p11 Locus Modulates Systemic Lupus Erythematosus Susceptibility

Objectives: This study employed genetic and functional analyses using OASIS meta-analysis of multiple existing GWAS and gene-expression datasets to identify novel SLE genes. Methods: Four hundred and ten genes were mapped using SNIPPER to 30 SLE GWAS loci and investigated for expression in three SLE GEO-datasets and the Cordoba {"type":"entrez-geo","attrs":{"text":"GSE50395","term_id":"50395"}}GSE50395-dataset. Blood eQTL for significant SNPs in SLE loci and STRING for functional pathways of differentially expressed genes were used. Confirmatory qPCR on SLE monocytes was performed. The entire 12p11 locus was investigated for genetic association using two additional GWAS. Expression of 150 genes at this locus was assessed. Based on this significance, qPCRs for DNM1L and KRAS were performed. Results: Fifty genes were differentially expressed in at least two SLE GEO-datasets, with all probes directionally aligned. DDX11, an RNA helicase involved in genome stability, was downregulated in both GEO and Cordoba datasets. The most significant SNP, rs3741869 in OASIS locus 12p11.21, containing DDX11, was a cis-eQTL regulating DDX11 expression. DDX11 was found repressed. The entire 12p11 locus showed three association peaks. Gene expression in GEO datasets identified DNM1L and KRAS, besides DDX11. Confirmatory qPCR validated DNM1L as an SLE susceptibility gene. DDX11, DNM1L and KRAS interact with each other and multiple known SLE genes including STAT1/STAT4 and major components of IFN-dependent gene expression, and are responsible for signal transduction of cytokines, hormones, and growth-factors, deregulation of which is involved in SLE-development. Conclusion: A genomic convergence approach with OASIS analysis of multiple GWAS and expression datasets identified DDX11 and DNM1L as novel SLE-genes, the expression of which is altered in monocytes from SLE patients. This study lays the foundation for understanding the pathogenic involvement of DDX11 and DNM1L in SLE by identifying them using a systems-biology approach, while the 12p11 locus harboring these genes was previously missed by four independent GWAS.