[en] Diabetic erectile dysfunction (DMED) is mainly attributed to oxidative stress, and Nrf2 plays an important role in cellular antioxidation and regulates NO production in the vascular endothelium. Probucol maintains endothelial function through its antioxidant activity. This study investigated the efficacy and mechanism of probucol in improving erectile function in streptozotocin-induced diabetic rats.

[en] Heating a mixture of the appropriate metal with iodine, followed by dissolving the products in THF or DME, and crystallization at low temperature has provided a simple route to microcrystalline molecular iodides of neodymium(II) and dysprosium(II), LnI₂(THF)₅ and LnI₂(DME)₃ (Ln=Dy, Nd). Prolonged drying of DyI₂(THF)₅ in vacuum yielded a violet powder of composition DyI₂(THF)₃. These crystalline complexes are thermally stable, but in the solution their stability is lower. (orig.)

[en] This work focuses on kinetic studies of anisole and triethylamine trihydrofluoride (fluorinating agent) on platinum electrode and acetonitrile as solvent, in order to get a better understanding of their anodic behavior. Results show that both compounds can be oxidized and some kinetic parameters are calculated: the diffusion coefficient within the working media, the anodic electronic transfer coefficient and the apparent intrinsic heterogeneous electronic transfer constant. An unusual variation of these parameters occurs within the chosen reaction conditions, particularly by varying the triethylamine trihydrofluoride concentration. Preliminary experiments for anodic fluorination of dimethoxy ethane (DME) and anisole were carried out and even if results show a possible electrofluorination for the DME (classically used as solvent), there is no fluorination of anisole when electrochemical microreactor was used.

[en] The synthesis and X-ray crystal structure of two new multinuclear thorium complexes are reported. The tetranuclear μ_4-oxo cluster complex Th_4(μ_4-O)(μ-Cl)_2I_6[κ"2(O,O"')-μ-O(CH_2)_2OCH_3]_6 and the dinuclear complex Th_2I_5[κ"2(O,O"')-μ-O(CH_2)_2OCH_3]_3(DME) (DME=dimethoxyethane) are formed by C-O bond activation of 1,2-dimethoxyethane (DME) mediated by thorium iodide complexes. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

[en] The different methods for the measurement of wire chamber aging were analyzed and a more correct procedure was proposed. A study of aging effects under intense radiation in drift chambers filled with dimethyl ether (DME), argon/carbon dioxide and argon/isobutane was performed. The influence of the materials and gain on the aging rate with DME was investigated. With a drift tube in clean conditions the relative gain drop R of 1.7%/(C/cm) was measured. For the drift chamber of the KEDR detector R is 45%/(C/cm). This corresponds to a 2% pulse height decrease per year at a gain of 10⁵ and flux of the charged particles of 1 kHz/cm². We conclude that, providing careful choice of the wire chamber and tubing materials, the DME filled drift chamber can be run without considerable aging effects. (orig.)

[en] Highlights: • A three component fuel combustion of diesel-DME-methanol investigation in HCCI engine. • The feasibility of DME and methanol replacement with diesel is evaluated in advanced exergetic framework. • The effect of 20% EGR on rate of pressure rise and ignition delay of blended fuel is considered. • D50 fuel exceeds in mechanical efficiency, D60 in exergy performance coefficient and lower irreversibility. • D80 shows minimum work exergy and maximum irreversibility. -- Abstract: A homogeneous compression ignition (HCCI) engine is taken for numerical investigation on the application of renewable fuels contained blends of methanol and DME with the base diesel fuel, which will be replaced with diesel in different percentages. First, the combustion and engine performance of the engine for two and three-component fuels will be discussed and secondly, the simultaneous effect of EGR in 20% by mass and engine speed in two blends of having maximum and minimum diesel proportion are compared and examined. The results indicate that the replacement of diesel with 20% of DME and 30% by methanol (D50M30DME20) at 1400 rpm generates a greater pressure and accumulated heat (AHR_peak = 330.569 J), whereas D80M20/2000 rpm/EGR20 gives a defective combustive performance with poor engine efficiency (IMEP = 7.21 bar). The interesting point is that the proposed optimum blend of D50 can achieve the best performance with 35% mechanical efficiency of 35%. The case of D60M10DME30 though dominates in terms of RPR = 3.177 bar/deg and ignition delay (ID = 4.54 CA) that gives the highest exergy performance coefficient (EPC = 2.063) due to its high work and lowest irreversibility.

[en] In methanol-to-hydrocarbon chemistry, methanol and dimethyl ether (DME) can act as methylating agents. Therefore, in this paper we focus on the different reactivity of methanol and DME towards benzene methylation in H-ZSM-5 at operating conditions by combining first principles microkinetic modeling and experiments. Methylation reactions are known to follow either a concerted reaction path or a stepwise mechanism going through a framework-bound methoxide. By constructing a DFT based microkinetic model including the concerted and stepwise reactions, product formation rates can be calculated at conditions that closely mimic the experimentally applied conditions. Trends in measured rates are relatively well reproduced by our DFT based microkinetic model. We find that benzene methylation with DME is faster than with methanol but the difference decreases with increasing temperature. At low temperatures, the concerted mechanism dominates, however at higher temperatures and low pressures the mechanism shifts to the stepwise pathway. This transition occurs at lower temperatures for methanol than for DME, resulting in smaller reactivity differences between methanol and DME at high temperature. Finally, our theory-experiment approach shows that the widely assumed rate law with zeroth and first order in oxygenate and hydrocarbon partial pressure is not generally applicable and depends on the applied temperature, pressure and feed composition.

[en] In this theoretical and experimental study, the ability of carbonyl fluoride (COF_2) and carbonyl chloride fluoride (COFCl) to form noncovalent interactions with the Lewis base dimethyl ether (DME) is assessed. From ab initio calculations, two stable complexes are found for COF_2·DME, both formed through a lone pair⋯π interaction. FTIR measurements on liquefied noble gas solutions, supported by ab initio calculations, statistical thermodynamical calculations and Monte Carle Free Energy Perturbation calculations, show that a 1:1 lone pair⋯π bonded complex is found in solution, with an experimental complexation enthalpy of −14.5(3) kJ mol"−"1. For COFCl·DME three lone pair⋯π complexes, as well as a Cl⋯O halogen bonded complex, are found from ab initio calculations. Experimentally, clear complex bands for 1:1 lone pair⋯π complexes are observed, with an experimental complexation enthalpy of −11.4(2) kJ mol"−"1. Furthermore, indications of the presence of a small amount of the halogen bonded complex are also observed.

[en] Highlights: • Ignition dynamics in turbulent DME/CH₄-air under RCCI condition is studied via DNS. • Low-temperature ignition transits to cool flame in the stratified DME/ CH₄-air mixture. • High-temperature autoignition is accelerated by the cool flame. • The four branches of typical tetrabranchial flames coexist in the field. -- Abstract: A study of ignition dynamics in a turbulent dimethyl ether (DME)/methane-air mixture under reactivity controlled compression ignition (RCCI) conditions was conducted using direct numerical simulation. Initially, the directly-injected DME and in-cylinder premixed methane-air mixture are partially mixed to form a mixing layer in between. A reduced DME/CH₄ oxidization mechanism, consisting of 25 species and 147 reaction steps, is developed and validated. Ignition is found to occur as a two-stage process. Low-temperature autoignition is first initiated in the fuel-rich part of the mixture and then transits to a cool flame, propagating towards the even richer mixture through a balanced reaction-diffusion mechanism. Cool flames not only develop in the mixing layer, but also in the initially stratified DME/methane-air mixture. The formation of high-temperature autoignition kernels is earlier than that in the homogeneous mixture at the same mixture fraction, which is thought to be accelerated by the cool flame. The expanding flames from high-temperature kernels are connected with the neighboring flames before they engulf the stoichiometric mixture iso-lines. The four branches of typical tetrabranchial flames, i.e. cool flame, fuel-rich premixed flame, diffusion flame, fuel-lean premixed flame coexist in the field. The fuel-lean premixed flame branch finally triggers the premixed methane-air flame. The multi-stage and multi-mode nature of the ignition process highlights the intractable challenge to model the RCCI engine combustion.

[en] 1-(2-Pyridylazo)-naphthol-2 has been successfully used as an amperometric reagent for the precise determination of small amounts of Prsup(III) and Ndsup(III). The lower detection limit is 0.10 mg in 10 ml of the test solution of metal ion, titrations have been performed at -0.6 V vs S.C.E., in any way hampered by presence of various cations and anions. (author)