Lipids in vascular function

Physiological and pathological vascular responses depend on the action of numerous intercellular mediators, ranging from hormones to gases like nitric oxide, proteins, and lipids. The last group consists not only of the different types of lipoproteins, but also includes a broad array of other lipophilic signaling molecules such as fatty acids, eicosanoids, phospholipids and their derivatives, sphingolipids and isoprenoids. Due to space limitations, it is impossible to discuss all the vascular effects of lipophilic mediators or compounds. Therefore, we will focus on one of the most important lipid-mediated diseases, atherosclerosis. Lipoproteins and especially their native or oxidized lipid compounds affect vascular function in many different ways, and these effects do not only modulate atherogenesis but are of paramount physiological and pathophysiological importance in other diseases, such as inflammation, tumor metastasis, or normal wound healing.     

Rippled and Helical MoS<Subscript>2</Subscript> Nanowire Catalysts: An Aberration Corrected STEM Study

Abstract  

Aberration corrected (C_s) scanning transmission electron microscopy (STEM) has been used for the first time to characterize MoS₂ catalysts (supported on Al₂O₃ substrates) to provide detailed information of its shape and structure. The high-resolution imaging reveals unprecedented morphologies present in the MoS₂ catalyst that have never been observed before with other experimental techniques because of the insufficient image contrast and/or resolution. High angle annular dark field (HAADF)-STEM images shows very clearly that the catalyst is formed by elongated chains with a twisted and helical structure. Based on the HAADF-STEM images, we built three atomic models to illustrate the different morphologies found in the MoS₂ catalyst. The existence of these nanostructures opens the posibility for novel catalyticaly active edge morphologies in MoS₂-based nanocatalysts.     

Synthesis of Sulfonated Carbon Nanocage and Its Performance as Solid Acid Catalyst

Abstract  

A carbon nanocage material (CKT) was first successfully sulfonated by introducing sulfophenyl groups on the surface of pore channels through benzenesulfonic acid-containing aryl radical in situ generated from the reaction of 4-aminobenzenesulfonic acid and isoamyl nitrite in water. The sulfonated carbon nanocage material (S-CKT) was characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, powder small-angle X-ray diffraction and nitrogen sorption measurements. The results showed that the S-CKT still possess the high specific surface area (787 m²/g) and uniform mesoporous (pore diameter 4.7 nm) structures, although the structure of S-CKT is slightly disorder, compared with its unsulfonated precursor. S-CKT, as a carbon-based solid acid catalyst, showed good catalytic performance and reusability in the cross-Aldol condensation of ketones with aromatic aldehydes under solvent-free condition.     

Nanosized Mn(acac)<Subscript>3</Subscript> Anchored on Amino Functionalized Silica for the Selective Oxidative Synthesis of 2-arylbenzimidazoles, 2-arylbenzothiazoles and Aerobic Oxidation of Benzoins in Water

Abstract  

Silica functionalized Mn(acac)₃ was prepared and employed for the one-pot oxidative synthesis of 2-arylbenzimidazoles, 2-arylbenzothiazoles; and oxidation of benzoins to benzils under air atmosphere using water as the reaction medium. Environmentally friendly procedure, chemoselectivity and excellent yields are main advantages of this procedure. In all the cases, the catalyst was found to be highly active and selective; passes hot filtration test successfully; and could be recycled several times with a slight loss of activity.     

Selective Oxidation of Glycerol Catalyzed by Rh/Activated Carbon: Importance of Support Surface Chemistry

Abstract  

Noble metal catalysts (Pt, Ir, Pd, Rh, Au) supported on activated carbon were assessed for glycerol oxidation. Rhodium is a highly efficient catalyst when the support has neutral or basic properties. The surface chemistry of activated carbon plays a key role in the performance.     

Gas-phase Photocatalytic Oxidation of Acrylonitrile on Sulphated TiO<Subscript>2</Subscript>: Continuous Flow and Transient Study

Abstract  

The gaseous products of photocatalytic oxidation (PCO) of acrylonitrile on sulphated P25 in concentrations from 10 to 100 ppm at 60 to 130 °C were CO₂, HCN and HNCO. This photocatalyst showed disproportionally improved performance at higher temperature and longer retention times. The temperature-programmed oxidation (TPO) after PCO disclosed possible reaction routes.     

Hyperbranched poly (amine-ester)-poly(ε-caprolactone) copolymer and their nanoparticles as camptothecin delivery system

A new amphiphilic hyperbranched poly (amine-ester)-poly(ε-caprolactone) copolymer (HPAE-co-PCL) was synthesized by ring-opening polymerization of ε-caprolactone and branched poly (amine-ester) (HPAE-OHs) with Sn(Oct)₂ as catalyst. The chemical structures of copolymers were determined by FT-IR, ¹H-NMR (¹³C-NMR), thermo gravimetric analysis apparatus (TGA) and differential scanning calorimetry (DSC). Camptothecin (CPT)-loaded copolymer nanoparticles were prepared by the oil-in water (o/w) emulsion technique method. Their physicochemical characteristics, e.g. morphology and nanoparticles size distribution were then evaluated by means of fluorescence spectroscopy, environmental scanning electron microscopy (ESEM), and dynamic light scattering (DLS). CPT-loaded nanoparticles assumed a spherical shape and have unimodal size distribution. It was found that the chemical composition of the nanoparticles was a key factor in controlling nanoparticles size, drug-loading content, and drug release behavior. As the molar ratio of ε-caprolactone to HPAE increased, the nanoparticles size and drug-loading content increased, and the drug release rate decreased. The antitumor activity of the CPT-loaded HPAE-co-PCL nanoparticles against human hepatoma HEPG2 cells was evaluated by 3-(4, 5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method. The CPT-loaded HPAE-co-PCL nanoparticles showed comparable anticancer efficacy with the free drug.