Toward Xeno-Free Differentiation of Human Induced Pluripotent Stem Cell-Derived Small Intestinal Epithelial Cells

The small intestinal epithelium has an important role in nutrition, but also in drug absorption and metabolism. There are a few two-dimensional (2D) patient-derived induced pluripotent stem cell (iPSC)-based intestinal models enabling easy evaluation of transcellular transport. It is known that animal-derived components induce variation in the experimental outcomes. Therefore, we aimed to refine the differentiation protocol by using animal-free components. More specifically, we compared maturation of 2D-cultured iPCSs toward small intestinal epithelial cells when cultured either with or without serum, and either on Geltrex or on animal-free, recombinant laminin-based substrata. Differentiation status was characterized by qPCR, immunofluorescence imaging, and functionality assays. Our data suggest that differentiation toward definitive endoderm is more efficient without serum. Both collagen- and recombinant laminin-based coating supported differentiation of definitive endoderm, posterior definitive endoderm, and small intestinal epithelial cells from iPS-cells equally well. Small intestinal epithelial cells differentiated on recombinant laminin exhibited slightly more enterocyte specific cellular functionality than cells differentiated on Geltrex. Our data suggest that functional small intestinal epithelial cells can be generated from iPSCs in serum-free method on xeno-free substrata. This method is easily converted to an entirely xeno-free method.     

A Novel Sprague-Dawley Rat Model Presents Improved NASH/NAFLD Symptoms with PEG Coated Vitexin Liposomes

Chronic liver disease (CLD) is a global threat to the human population, with manifestations resulting from alcohol-related liver disease (ALD) and non-alcohol fatty liver disease (NAFLD). NAFLD, if not treated, may progress to non-alcoholic steatohepatitis (NASH). Furthermore, inflammation leads to liver fibrosis, cirrhosis, and hepatocellular carcinoma. Vitexin, a natural flavonoid, has been recently reported for inhibiting NAFLD. It is a lipogenesis inhibitor and activates lipolysis and fatty acid oxidation. In addition, owing to its antioxidant properties, it appeared as a hepatoprotective candidate. However, it exhibits low bioavailability and low efficacy due to its hydrophobic nature. A novel rat model for liver cirrhosis was developed by CCL4/Urethane co-administration. Vitexin encapsulated liposomes were synthesized by the ‘thin-film hydration’ method. Polyethylene glycol (PEG) was coated on liposomes to enhance stability and stealth effect. The diseased rats were then treated with vitexin and PEGylated vitexin liposomes, administered intravenously and orally. Results ascertained the liposomal encapsulation of vitexin and subsequent PEG coating to be a substantial strategy for treating liver cirrhosis through oral drug delivery.     

Preparation, characterisation of thermally treated Algerian dolomite powders and application to azo-dye adsorption

Dolomite powder from Ouled Mimoun, Tlemcen (western region of Algeria) was thermally treated within the temperature range 450-1000 °C. The modifications undergone by dolomite, inherent to thermal treatment, were investigated from X-ray diffraction patterns. The results were also discussed using scanning electronic microscopy and nitrogen adsorption. The XRD data, analysed from X Pert Plus program, showed that the dolomite phase ceases at 700 °C and is relayed by the formation of in situ calcite and periclase. The crystallographic parameters of these two phases tend towards that of pure periclase and calcite at 1000 and 900 °C, respectively. SEM analysis indicated that the morphological properties were profoundly affected. SEM images of D-1000 (sample treated at 1000 °C) indicated that the original particle shape of dolomite (presence of discrete grains having sharp edges with presence of cleavages) was totally destroyed, leading to small spherical particles with a diameter of 0.1 μm. The specific surface area value of D-1000 increased more than 6 times against that of the raw dolomite. Adsorption of azo-dye Orange I from aqueous solutions onto untreated and treated dolomites was also reported. The isotherms were of L-type. The interaction was explained by electrostatic considerations between sulfonate groups of the dye (D-SO₃Na), which are dissociated in the aqueous system, and positively charged adsorption sites. The affinity of orange I for the dolomitic solids follows the sequence D-900 > D-1000 > D-800 > > D-600 > raw dolomite. The maximum retention capacity shown by D-900 was explained and correlated with its crystallographic properties.     

Complex structural contribution of the morphotropic phase boundary in Na0.5Bi0.5TiO3 - CaTiO3 system

The correlation between structure and dielectric properties of lead-free (1-x)Na_0.5Bi_0.5TiO₃ - xCaTiO₃ ((1-x)NBT - xCT) polycrystalline ceramics was investigated systematically by X-ray diffraction, combined with impedance spectroscopy for dielectric characterizations. The system shows high miscibility in the entire composition range. A morphotropic phase boundary (MPB), at 0.09?≤?x?<?0.15 was identified where rhombohedral and orthorhombic symmetries coexist at room temperature. The fraction of orthorhombic phase increases gradually with x in the MPB region. Dielectric measurements reveal that the relative permittivity increase with addition of Ca²⁺. This behavior is unusual with this kind of doping. A thermal hysteresis occurred only in the MPB composition which varies in a non-monotonically manner with x, detected by dielectric properties. This phenomenon is related to the crystalline microstructure by a linear relationship between the fraction of each phase and dielectric properties, and, more precisely, to the strong interaction between rhombohedral and orthorhombic phases.     

Effect of high temperature and the role of sulfate on adsorption behavior and effectiveness of AMPS®‐based cement fluid loss polymers

The fluid loss control performance of 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS®)‐based copolymers added to cement slurries was studied at 27 and 100°C, respectively. It was found that effectiveness of these fluid loss additives solely relies on achievement of a high adsorbed amount on the surface of cement. At elevated temperature (100°C), CaAMPS®‐N,N‐dimethyl acrylamide copolymer (CaAMPS®‐co‐NNDMA) exhibits reduced adsorption and hence decreased fluid loss control of the cement slurry. The reason behind this behavior is poor calcium binding capability of the sulfonate anchor groups, which coordinate with calcium atoms present on the mineral surface. Whereas, an increase in the sulfate concentration present in cement pore solution instigates partial coiling of CaAMPS®‐co‐NNDMA and causes only a slight influence on the performance of this copolymer. The elevated sulfate content results from thermal degradation of ettringite, a cement hydrate mineral produced during the early stages of cement hydration. Incorporation of minor amounts (～ 1.3 mol %) of maleic anhydride into this copolymer produces a terpolymer, which exhibits higher and more stable adsorption, even at high temperature. This effect is owed to the presence of homopolymer blocks of polycarboxylates distributed along the polymer trunk. On mineral surfaces, they present much stronger anchor groups than sulfonate functionalities, as evidenced by their higher calcium binding capability. Consequently, fluid loss performance of CaAMPS®‐co‐NNDMA‐co‐MA is little affected by temperature. Understanding the influence of temperature on the physicochemical interactions occurring between additives and the mineral surface can help to design more effective admixtures suitable for high temperature applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Polyelectrolyte complexes from polyethylene imine/acetone formaldehyde sulfite polycondensates: A novel reagent for effective fluid loss control of oil well cement slurries

When used by itself, polyethylene imine (PEI) does not perform well as cement fluid loss additive. Its combination with acetone formaldehyde sulfite (AFS) polycondensate, however, exhibits excellent filtration control. The mechanism underlying this synergistic effect was studied and the conditions producing best results were determined. For optimum performance, PEI and AFS must be reacted with each other to yield a polyelectrolyte complex (PEC) (d ～ 5–10 μm), which effectively plugs the pores of the cement filter cake. Composition, size, and effectiveness of the PEC are strongly influenced by the anionic charge amount of the AFS dispersant. Ionic interactions between cationic imine functionalities of PEI and anionic sulfonate groups existing in AFS were confirmed by conductivity, infrared, zeta potential, and particle size measurements. For AFS samples possessing different degrees of sulfonation, the largest particle size and hence best fluid loss performance of the PEC was found to occur at a PEI:AFS molar ratio, which corresponds to neutral charge. Occurrence of large PEC particles (d ～ 5 μm) within the cement filter cake pores was visualized by scanning electron microscopy, and their stability in highly alkaline cement pore solution was confirmed by particle size measurement. Other anionic polyelectrolytes may be used to yield such PECs with PEI to provide effective fluid loss control for cement slurries. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Strain‐induced deformation mechanisms of polylactide plasticized with acrylated poly(ethylene glycol) obtained by reactive extrusion

This work aimed at identifying the tensile deformation mechanisms of an original grade of plasticized polylactide (pPLA) obtained by reactive extrusion. This material had a glass transition temperature of 32.6 °C and consisted of a polylactide (PLA) matrix grafted with poly(acryl‐poly(ethylene glycol)) (poly(Acryl‐PEG)) inclusions. pPLA behaved like a rubber‐toughened amorphous polymer at 20 °C, and its tensile behavior evolved toward a rubbery semicrystalline polymer with increasing temperature. The drawing of pPLA involved orientation of amorphous and crystalline chains, crystallization, and destruction of crystals. It was found that crystal formation and crystal destruction were in competition below 50 °C, resulting in a constant or slightly decreasing crystallinity with strain. Increasing temperature enhanced crystal formation and limited crystal destruction, resulting in an increased crystallinity with the strain level. Drawing yielded a transformation of the initial spherical poly(Acryl‐PEG) inclusions into ellipsoids oriented in the tensile direction. This mechanism may engender the formation of nanovoids within the inclusions due to a decreased density, assumed to be responsible for the whitening of the specimen. © 2015 Society of Chemical Industry     

Influence of different viscosity grade cellulose-based polymers on the development of valsartan controlled release tablets

This work is based on formulating and optimizing controlled release (CR) valsartan (160 mg) tablets using different viscosity grades of the cellulosic polymer. The objective was to develop an effective once-daily drug delivery system of this cardiovascular agent. Central composite design was used for designing the formulations. Polymers used were Methocel® K4M, K15M and K100M. Compatibility of excipients with active was studied through FT-IR. Micromeritic properties were determined and formulations exhibiting appropriate flow characteristics were compressed. Swelling behavior and in vitro buoyancy effect were studied and response surface curves were constructed to optimize the formulation. Multi-point dissolution profiles of valsartan CR tablets at pH 1.2, 4.5 and 6.8 were obtained. Model-dependent and model-independent methods were performed including f2, stability test as per ICH guidelines and ANOVA. FT-IR studies revealed the compatibility of valsartan with all excipients. Formulation K4T9 (containing 25% K4M polymer) was selected to be the best optimized trial, based on physical properties and controlled release profile (23% at 4 h, 82% at 16 h and 100% at 24 h). Results of buoyancy and swelling behavior indicated that HPMC-K4M polymer exhibited excellent floating lag time and swelling indexes. In vitro drug release kinetics showed that formulation K4T9 displayed Korsmeyer–Peppas drug release pattern with r value > 0.99. The manufacturing process of K4T9 was also found to be reproducible with a shelf life period of 41 and 36 months at room temperature and accelerated conditions, respectively. Valsartan CR matrix-based formulation was successfully prepared with Methocel K4M retardant.     

Ternary Blends of Renewable Fast Pyrolysis Bio-Oil,Advanced Bioethanol,and Marine Gasoil as Potential Marine Biofuel

An alternative for reducing emissions from marine fuel is to blend bio-oil from lignocellulose non-edible feedstocks to diesel fossil fuels. Phase diagrams of the ternary systems were built to represent the transition from heterogeneous regions to homogeneous regions. Four homogeneous blends of bio-oil of eucalyptus-bioethanol-marine gasoil were experimentally characterized with respect to the most important fuel parameters for marine engines: water content, flash point, low heating value, viscosity, and acidity. Blends with closer properties to marine gasoil replacement, lower costs, and environmental impacts should be tested for large engines.