Reduced secretion of triacylglycerol in CaCo-2 cells transfected with intestinal fatty acid-binding protein

The fatty acid-binding proteins are hypothesized to be involved in cellular fatty acid transport and trafficking. We established CaCo-2 cells stably transfected with intestinal fatty acid-binding protein (I-FABP) and examined how the expression of this protein may influence fatty acid metabolism. I-FABP expression was detectable in I-FABP-transfected cells, whereas parent CaCo-2 cells as well as mock-transfected cells failed to express detectable levels of I-FABP mRNA or protein at any stage of differentiation. For studies of lipid metabolism, cells were incubated with [¹⁴C]oleic acid in taurocholate micelles containing monoolein, and distribution of labeled fatty acid in cellular and secreted lipids was examined. In one transfected cell clone, expressing the highest level of I-FABP, labeled cellular triacylglycerol increased approximately twofold as compared to control cells. The level of intracellular triacylglycerol in two other I-FABP-transfected clones resembled that of control cells. However, secretion of triacylglycerol was markedly reduced in all the I-FABP-expressing cell lines. Our data suggest that increased expression of I-FABP leads to reduced triacylglycerol secretion in intestinal cells.     

Activation of Pozzolanic Reaction of Hydrated Portland Cement Fly Ash Pastes in Sulfate Solution

The activation of the pozzolanic reaction of fly ash in portland cement paste immersed in sulfate solution has been studied. Mixtures of two Spanish fly ashes (ASTM class F) with 0%, 15%, and 35% replacement of portland cement by fly ash were immersed in Na₂SO₄ solution, of 2880 ppm SO₄²⁻ concentration, for a period of 90 days. The resistance of the different mixtures to the sulfate attack was evaluated using the Koch-Steinegger test. The results showed that all of the mixtures were sulfate resistant, despite the high Al₂O₃ content of the fly ash. The diffusion of SO₄²⁻ and Na⁺ ions through the pore solution activated the pozzolanic reactivity of the fly ashes, causing microstructural changes, which were characterized by X-ray diffraction (XRD), mercury intrusion porosimetry (MIP), and scanning electron microscopy (SEM). As a result, the flexural strength of the mixtures increased, principally for the fly ash of a lower particle size and 35% of addition.     

Metastable Phase Selection and Partitioning in ZrO2—MgO Processed from Liquid Precursors

Aqueous mixtures of either zirconium acetate or zirconium nitrate and magnesium nitrate were dried and subsequently pyrolyzed at fast heating rates (upquenching) to form metastable crystalline phases of ZrO₂ with various degrees of MgO supersaturation. The crystallization temperature was determined to be 380°C for the zirconium acetate, and 270°C for the zirconium nitrate at a heating rate of 5°C/min. The crystalline structures were characterized as a function of MgO content and thermal history for specimens containing 0 to 30 mol% MgO. Upquenching to 900°C, where monoclinic ( m ) ZrO₂ and MgO are the equilibrium phases, yielded single-phase tetragonal ( t ) ZrO₂ (<8 mol% MgO), single-phase cubic ( c ) ZrO₂ (9 to 17 mol% MgO), and two-phase c -ZrO₂+ MgO structures (>17 mol% MgO). The composition for which T ₀( t/c ) = 900°C was estimated as 9 ± 1 mol% MgO. Compositions crystallizing as metastable t -ZrO₂ (<8 mol% MgO) partitioned at higher temperatures and/or longer times into two-phase mixtures, following the general sequence t → t + m → m + MgO. Similarly, compositions forming metastable c -ZrO₂ (10 to 30 mol% MgO) partitioned in the following sequence: c → c + t + MgO → t + MgO → t + m + Mgo → m + Mgo. The initial phase selection and subsequent partitioning sequence are discussed in light of phase hierarchies predicted from thermodynamic concepts and kinetic constraints which are introduced by the solute partitioning required to achieve equilibrium.     

AFM observation of polyethylene single crystals: selective handedness of screw dislocations in a chair type

The three-dimensional morphology of polyethylene single crystals grown from dilute solution has been examined by atomic force microscopy. Single crystals were deposited on a soft ground of aqueous solution of poly(vinyl alcohol) (PVA) to avoid the collapse of thin lamellar crystals with thickness of 10 nm. The observation of single crystals on dried PVA clarifies the morphology of a chair type crystal as well as well-known hollow pyramidal type. It has been confirmed that the screw dislocations in the chair type follow a selection rule of the handedness in a manner to relieve the distortion in the chair type.     

Nutritional recovery of mild and moderately malnourished children under two different treatment approaches (ambulatory versus day-care)

This retrospective analysis was conducted between May 1997 and May 2000 at the Centro de Atención Nutricional Infantil de Antímano, CANIA, in Caracas, Venezuela to assess the efficacy of two treatments (ambulatory versus day-care) of mild and moderate malnourished children. Inclusion criteria were: children under 10 years old with mild and moderate malnourishment, who attended a minimum of 3 control visits during a period of 12 months. One hundred fourteen malnourished children were included: fifty seven in ambulatory treatment and fifty seven in day-care treatment paired per nutritional diagnosis, gender and age (thirty nine mild and eighteen moderate malnourished children). The nutritional recovery criterion was weight for height above tenth percentile. No relation was found between treatment approaches and nutritional recovery at 3 and 6 months of treatment. In the group of mild malnourished children, the percentage of recovered patients at 3 months of treatment, that kept their recovered condition at 6 months was 83% (15/18) in the ambulatory treatment and 82% (18/22) in the day-care treatment Age of children, associated disease, acute morbidity, dietetic risk and mother's education and age were not associated with nutritional recovery at 6 months of treatment (p > 0.05). The day-care approach resulted as effective as ambulatory in mild malnourished children. In moderate malnourished new studies will need to be conducted with greater number of patients.     

Thermal strain of high strength polyethylene fiber in low temperature

High strength polyethylene fiber (Toyobo, Dyneema® fiber: hereinafter abbreviated to DF) has a negative thermal expansion coefficient. Relation between fiber structure and thermal strain of DF used as reinforcement of DF reinforced plastic (DFRP) for cryogenic use was investigated. The crystallinities and orientation angles of several kinds of polyethylene fibers having different modulus from 15 to 134Gpa (herein after abbreviated to DFs) were measured by NMR and X‐ray. We obtained the parameters of the mechanical series‐parallel model composed of crystal and amorphous by crystallinity and modulus. Thermal expansion coefficients of DFs were estimated by mechanical series‐parallel model. All DFs having different modulus showed negative thermal expansion coefficients in the temperature range from 180 to 300K, and absolute values of those markedly increased by increasing tensile modulus of DF. The estimated thermal expansion coefficients showed negative values, and thermal strains showed a similar curve to observed ones mostly. Average thermal expansion coefficients in the temperature range from 180 to 300K estimated by mechanical model agreed with the observed ones. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2918–2925, 2004     

Dissolution and Separation of Ruthenium in Borosilicate Glass

The behavior of ruthenium oxide (RuO₂) in aluminoborosilicate glass used for the stabilization of nuclear waste was investigated. It was found that 0.025 mass% RuO₂ dissolved as Ru⁴⁺ in the glass at 1400°C, which caused the glass to turn yellow. When the RuO₂ amount was 0.05 mass%, needle-shaped crystals formed in the glass during slow cooling. If the added amount exceeded 0.1 mass% and the cooling rate was slow, it separated rapidly and the glass became pale after cooling. No dissolution of ruthenium was detectable after melting at 1200°C.     

Template-free synthesis and adsorption properties of microporous crystal AlPO4-H3

A microporous aluminophosphate molecular sieve, AlPO₄-H3, was prepared without using organic templates. It was crystallized at temperatures as low as 90 °C from aluminophosphate gels with a molar ratio of Al₂O₃/P₂O₅1; the addition of seed crystals was essential. AlPO₄-H3 was topotactically and irreversibly converted into AlPO₄-D at 300 °C, which adsorbed water up to 0.2 ml/g at 25 °C, although nitrogen gas was hardly adsorbed at liquid nitrogen temperature.     

Review on the durability of exterior wood coatings with reduced VOC-content

The main factors that contribute to the durability of exterior wood coatings are discussed with special emphasis on the recent developments to reduce the volatile organic compound (VOC) content in these types of coating like water-borne acrylic dispersions, water-borne alkyds or high solid alkyd formulations. The performance of a coating during outdoor weathering is determined by: photochemical degradation (only for paints that are not opaque), moisture permeability in relation to wood-moisture content and dimensional change and the microbiological degradation at the wood–coating interface. The results from various outdoor weathering studies are discussed. These studies show fairly consistent results with respect to the influence of coating type or wood species. However, a sound theory about the mechanism of failure, that can related to basic properties of the coating or the binder, has not yet been established.     

Water‐soluble/dispersible carbazole‐containing random and block copolymers by nitroxide‐mediated radical polymerisation

A series of carbazole‐containing water‐dispersible poly(acrylic acid)‐b‐(9‐(4‐vinylbenzyl)‐9H‐carbazole) block copolymers (poly(AA)‐b‐poly(VBK)) and water‐soluble poly(methacrylic acid‐ran‐(9‐(4‐vinylbenzyl)‐9H‐carbazole)) (poly(MAA‐ran‐VBK)) random copolymers were synthesised in a controlled manner (i.e. low polydispersities $(\overline {M_{{\rm w}} } /\overline {M_{n} } < 1.3)$ by nitroxide‐mediated polymerisation (NMP) using an SG1‐based alkoxyamine initiator, BlocBuilder. Poly(AA)‐b‐poly(VBK) block copolymers were most easily accessed by using poly(AA) in its protected form as the macroinitiator for the 9‐(4‐vinylbenzyl)‐9H‐carbazole (VBK) block. Controlled polymerisation of MAA was accomplished using an excess of 10 mol.% SG1 relative to BlocBuilder with VBK as controlling co‐monomer (initial molar feed content f_VBK,0 = 0.03–0.20) in dimethylformamide at 80°C. Poly(MAA‐ran‐VBK) copolymers with a final VBK molar composition of F_VBK < 0.30 resulted in water‐soluble copolymers. In addition, as macroinitiators, poly(MAA‐ran‐VBK)s were sufficiently pseudo‐living to reinitiate a second batch of monomer (90 mol.% methyl methacrylate with styrene) in organic solvent and by ab initio, surfactant‐free emulsion polymerisation. In both cases, low polydispersity, amphiphilic block copolymers resulted $(\overline {M_{{\rm w}} } /\overline {M_{{\rm n}} } < 1.3)$ . © 2012 Canadian Society for Chemical Engineering