Stable Synthetic Bacteriochlorins for Photodynamic Therapy: Role of Dicyano Peripheral Groups,Central Metal Substitution (2H,Zn, Pd), and Cremophor EL Delivery

A series of four stable synthetic bacteriochlorins was tested in vitro in HeLa cells for their potential in photodynamic therapy (PDT). The parent bacteriochlorin (BC), dicyano derivative (NC)₂BC and corresponding zinc chelate (NC)₂BC–Zn and palladium chelate (NC)₂BC–Pd were studied. Direct dilution of a solution of bacteriochlorin in an organic solvent (N,N‐dimethylacetamide) into serum‐containing medium was compared with the dilution of bacteriochlorin in Cremophor EL (CrEL; polyoxyethylene glycerol triricinoleate) micelles into the same medium. CrEL generally reduced aggregation (as indicated by absorption and fluorescence) and increased activity up to tenfold (depending on bacteriochlorin), although it decreased cellular uptake. The order of PDT activity against HeLa human cancer cells after 24 h incubation and illumination with 10 J cm^?2 of near‐infrared (NIR) light is (NC)₂BC–Pd (LD₅₀=25 nM ) > (NC)₂BC > (NC)₂BC–Zn ≈ BC. Subcellular localization was determined to be in the endoplasmic reticulum, mitochondria and lysosomes, depending on the bacteriochlorin. (NC)₂BC–Pd showed PDT‐mediated damage to mitochondria and lysosomes, and the greatest production of hydroxyl radicals as determined using a hydroxyphenylfluorescein probe. The incorporation of cyano substituents provides an excellent motif for the enhancement of the photoactivity and photostability of bacteriochlorins as PDT photosensitizers.     

T–T–T behaviour of bioactive glasses 1–98 and 13–93

In this work crystallization kinetics of bioactive glasses 1–98 and 13–93 are discussed. Within a certain temperature–time window these glasses can be hot worked into various products without interfering with crystallization. The crystallization was studied isothermally by heating glass plates at different temperatures for different times. Phases in the samples were studied through XRD and SEM analyses. The nucleation-like curves and crystallization characteristics were measured with DTA. The temperature of maximum nucleation was measured for glass 1–98 at 725 °C and for 13–93 at 700 °C. The activation energy of crystallization of both glasses was 280 kJ/mol. The Johnson–Mehl–Avrami exponent and the SEM micrographs of the samples suggested surface crystallization. The primary crystalline phase was wollastonite. The growth rate of the crystallized surface layer was 1 order of magnitude higher in the plates of 1–98 than in 13–93. The results can be utilized to optimize the parameters in hot-working of the glasses.     

Exfoliated production of single- and multi-layer graphenes and carbon nanofibres from the carbonisation of a co-polymer

Non-catalysed growth methodologies of carbon nanomaterial synthesis can represent lower costs and greener approaches and cause less damage to the nanomaterial. During the carbonisation of a polyacrylonitrile-based co-polymer, carbon nanofibres (CNFs) and single- and multi-layer graphenes (SLG and MLG) are generated. The accumulated fragmentation products of the co-polymer coalesce to form CNFs that radiate away from the monolith, whose dimensions are linked to their template growth along crests, which were formed from the out-gassing of volatile products of the polymer during the stabilisation step. The slight shrinkage of the carbonising monolith also leads to exfoliation of larger areas of the surface yielding single- and multi-layered graphenes. These results reveal a potentially useful process for the facile production of carbon nanomaterials.     

The development of canola oil based bio‐resins

Bio‐based resins made from vegetable oils offer a sustainable alternative to petroleum‐based thermoset resins. The thermosetting resin systems we have developed from epoxidized canola oil and the polyurethanes we have produced from canola oil‐based polyols show promise as cost‐effective materials incorporating a high renewable content. Here we outline the use of canola oil based bio‐resins in composite boards, and in polyurethane adhesive and insulating foam applications.     

Computer analysis of a polymer coating exposed to field weather conditions

A heat and moisture transfer model was used to study weathering of polymeric materials, such as paint, asphalt, sealants, plastics, textiles, and polymeric composites. Three damage indices, related to temperature changes, humidity changes, and time of wetness, respectively, were introduced to quantify adverse effects of climate. The variation of these indices was investigated for a hot and humid climate (Miami, FL) and a hot and dry climate (Phoenix, AZ). In addition, the relative effects of solar radiation, surface wetting by rain and dew condensation, and variations in outdoor temperature and relative humidity on the three damage indices were investigated. 100 Bureau Dr., Stop 8621, Gaithersburg, MD 20899-8621.     

Dynamic modeling of a multiple hearth furnace for kaolin calcination

A dynamic model of a multiple hearth kaolin calciner has been developed and is presented in this article. This model describes the physical‐chemical phenomena taking place in the six furnace parts: the solid phase, gas phase, walls, cooling air, rabble arms, and the central shaft. The solid phase movement, in particular, is described by a novel mixing model. The mixing model divides the solid bed in a hearth into volumes and the distribution of their contents, after one full central shaft rotation, is identified by the pilot experiments. First, the model is validated by the industrial data, and then the dynamics of the multiple hearth furnace is studied by introducing step changes to the three manipulated variables: the feed rate, and the gas, and air flows supplied. The responses of the gas phase temperature and solid bed component profiles are analysed and the results are discussed. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3683–3698, 2015     

On the use of the atomic force microscope to monitor physical degradation of polymeric coating surfaces

The atomic force microscope (AFM) was used to monitor changes in surface features of an acrylic melamine coating that was exposed to a variety of conditions. Exposure to ultraviolet (UV) radiation and high relative humidity caused general roughening of the surface and the formation of pits. Further, the damage of the coating surface was much more substantial for exposure to high relative humidity compared to exposure to dry environments. This difference in degradation rates correlated with measurements of chemical degradation determined using infrared spectra that were acquired along with the AFM images. Building Materials Division, 100 Bureau Dr., Stop 8621, Gaithersburg, MD 20899-8621.