Adaptation of Oxidative Phosphorylation Machinery Compensates for Hepatic Lipotoxicity in Early Stages of MAFLD

Alterations in mitochondrial function are an important control variable in the progression of metabolic dysfunction-associated fatty liver disease (MAFLD), while also noted by increased de novo lipogenesis (DNL) and hepatic insulin resistance. We hypothesized that the organization and function of a mitochondrial electron transport chain (ETC) in this pathologic condition is a consequence of shifted substrate availability. We addressed this question using a transgenic mouse model with increased hepatic insulin resistance and DNL due to constitutively active human SREBP-1c. The abundance of ETC complex subunits and components of key metabolic pathways are regulated in the liver of these animals. Further omics approaches combined with functional assays in isolated liver mitochondria and primary hepatocytes revealed that the SREBP-1c-forced fatty liver induced a substrate limitation for oxidative phosphorylation, inducing enhanced complex II activity. The observed increased expression of mitochondrial genes may have indicated a counteraction. In conclusion, a shift of available substrates directed toward activated DNL results in increased electron flows, mainly through complex II, to compensate for the increased energy demand of the cell. The reorganization of key compounds in energy metabolism observed in the SREBP-1c animal model might explain the initial increase in mitochondrial function observed in the early stages of human MAFLD.     

Spray drying with a two-fluid nozzle to produce fine particles: Atomization,scale-up,and modeling

This article presents experimental and modeling work to complete previously reported work on spray drying. Back-calculated droplet sizes have been verified by measurements with a laser imaging rig. Flow patterns in a cylindrical spray chamber have been simulated by computational fluid dynamics and demonstrated that droplet residence times are much shorter than expected. A droplet tracking population balance model has been implemented in gSOLIDS and shows how drying times vary with droplet diameter. Particle collection by cyclone and bag filter have also been compared experimentally.     

Der einfluß von faseroberflächen auf die matrixhärtung bei faserverbundwerkstoffen

The influence of extraction of reinforced fibres on surface properties and the curing reaction of epoxy resin matrix in composites were investigated. With increasing fibre surface polarity, as the result of the extraction, the resin wettability was improved and the reaction rate of curing of the epoxy resin matrix increased. The wettability and the reaction rate oppositely decreased with decreasing fibre surface polarity.     

Flammability of layered silicate epoxy nanocomposites combined with low‐melting inorganic ceepree glass

Tetraphenylphosphonium modified layered silicate epoxy nanocomposite (EP/TPPMMT) combined with low‐melting silicate glass, Ceepree (CP) is investigated by thermal analysis, flammability tests and cone calorimeter at different heat fluxes. Adding CP and TPPMMT does not change the pyrolysis apart from increasing inorganic residue. The total heat evolved (THE) is changed insignificantly, as neither relevant additional carbonaceous charring nor flame inhibition occurs. However, flame retardancy is clearly observed due to an inorganic‐carbonaceous surface protection layer. The peak heat released rate (PHRR) is reduced by around 32–42% when 5 wt% TPPMMT is added, and 51–63% when 10 wt% CP is added. PHRR reduction less than expected is observed when both additives are combined. The reduction is greater than that achieved by using TPPMMT but less than when only CP is used. The morphology of fire residue is investigated by scanning electron microscope on different length scales and turns out to be the key to understanding the efficiency of flame retardancy. The fire residue of EP/CP shows a layered structure, whereas separated columns limit the barrier properties for EP/5%TPPMMT on the micrometer scale. Columns dominating the fire residue structure of EP/5%TPPMMT/10%CP deteriorate the fire retardancy, whereas a more integral structure at the top of the residue causes the improvement over EP/5%TPPMMT. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

Biodegradable block copolymers with poly(ethylene oxide) and poly(glycolic acid‐valine) blocks

Biodegradable ABA triblock copolymers with poly(ethylene oxide) and poly(glycolic acid‐valine) blocks were synthesized via ring‐opening polymerization of cyclo(glycolic acid‐valine) using Ca‐alcoholates of hydroxytelechelic PEO as the initiator. The L‐valine residue racemized during copolymerization of cyclo(glycolic acid‐valine). The crystallization of the block copolymers decreases with decreasing PEO content in the triblock copolymers and with increasing length of the poly(glycolic acid‐valine) block. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2916–2919, 2002     

Block copolymers comprising poly(ethylene oxide) and poly(hydroxyethyl methacrylate) blocks: synthesis and characterization

Monofunctional poly(ethylene oxide) macroinitiators with a molecular weight of 2000, 5000, 10?000, 20?000 and bifunctional poly(ethylene oxide) macroinitiators with a molecular weight of 20?000 were used for the atom transfer radical polymerisation (ATRP) of hydroxyethyl methacrylate (HEMA) in ethylene glycol as a solvent. The polymerisation proceeds in a controlled way up to high conversions. The molecular weight of the obtained copolymers increases linearly with conversion. A high rate of polymerisation was observed for the ATRP of HEMA. The effect of the poly(ethylene oxide) moiety on the course of the reaction is limited to solvating effects. The surface analysis of poly(ethylene oxide)/poly(hydroxyethyl methacrylate) block copolymers by means of atomic force microscopy in tapping mode using phase imaging shows phase separated domains with characteristic features related to the volume fraction of the respective blocks.     

Syntheses and reactions of urethanes of cellobiose and cellulose-containing uretdione groups

Urethanes of cellobiose and cellulose-containing uretdione groups are synthesized by the reaction of aliphatic and aromatic diisocyanate uretdiones with the saccharides. The syntheses are performed as a heterogeneous reaction in dimethyl acetamide using dibutyl tin dilaurate as a catalyst, as well as a homogeneous reaction in dimethyl acetamide-lithium chloride. Thus, Semisynthetic prepolymers are formed that offer the reactivity of (blocked) isocyanate groups. To demonstrate their reactivity, ring opening of the uretdiones is performed by the addition of a secondary amine to yield the corresponding ureas.     

Contents List and Abstracts from the Journal of the Adhesion Society of Japan

FTIR reflection spectroscopy was used to characterize thin films of a cyanurate prepolymer on evaporated aluminium and on silicon single crystal wafers. Both substrates are covered by their native oxides. The optical function of the prepolymer is derived from ATR measurements. The measured thin film reflectance spectra have to be interpreted in comparison with the corresponding bulk spectra obtained by simulation. All samples re-produce the bulk composition. The cyanate groups of the prepolymer are not involved in specific intermolecular interactions or in preferential orientation. This is also found for the triazine rings on Si. On Al, however, a considerable excess of triazine rings are oriented parallel to the interface. The vibration frequencies of the triazine groupings that are perpendicular to the Al substrate show a red shift to some 2–8 c^?1. This special interaction effect does not occur on Si. Both the preferential orientation and the specific inter-molecular interaction act at least 100 nm into the prepolymer layer.     

Evolution of a fourth generation catalyst for the amination and thioetherification of aryl halides

Many active pharmaceuticals, herbicides, conducting polymers, and components of organic light-emitting diodes contain arylamines. For many years, this class of compound was prepared via classical methods, such as nitration, reduction and reductive alkylation, copper-mediated chemistry at high temperatures, addition to benzyne intermediates, or direct nucleophilic substitution on particularly electron-poor aromatic or heteroaromatic halides. However, during the past decade, palladium-catalyzed coupling reactions of amines with aryl halides have largely supplanted these earlier methods. Successive generations of catalysts have gradually improved the scope and efficiency of the palladium-catalyzed reaction. This Account describes the conceptual basis and utility of our latest, "fourth-generation" palladium catalyst for the coupling of amines and related reagents with aryl halides. In the past five years, we have developed these catalysts using the lessons learned from previous generations of catalysts developed in our group and in other laboratories. The ligands on the fourth-generation catalyst combine the chelating properties of the aromatic bisphosphines of the second-generation systems with the steric properties and strong electron donation of the hindered alkylphosphines of the third-generation systems. The currently most reactive catalyst in this class is generated from palladium and a sterically hindered version of the Josiphos family of ligands that possesses a ferrocenyl-1-ethyl backbone, a hindered di-tert-butylphosphino group, and a hindered dicyclohexylphosphino group. This system catalyzes the coupling of aryl chlorides, bromides, and iodides with primary amines, N-H imines, and hydrazones in high yield. The reaction has broad scope, high functional group tolerance, and nearly perfect selectivity for monoarylation. It also requires the lowest levels of palladium that have been used for C-N coupling. In addition, this latest catalyst has dramatically improved the coupling of thiols with haloarenes to form C-S bonds. Using ligands that lacked one or more of the structural elements of the most active catalyst, we examined the effects of individual structural elements of the Josiphos ligand on catalyst activity. This set of studies showed that each one of these elements contributes to the high reactivity and selectivity of the catalyst containing the hindered, bidentate Josiphos ligand. Finally, we examined the effect of electronic properties on the rates of reductive elimination to distinguish between the effect of the properties of the M-N sigma-bond and the nitrogen electron pair. We have found that the effects of electronic properties on C-C and C-N bond-forming reductive elimination are similar. Because the amido ligands contain an electron pair, while the alkyl ligands do not, we have concluded that the major electronic effect is transmitted through the sigma-bond.