2-Pyridyl-benzimidazole-Pd(II)/Pd(0) Supported on Magnetic Mesoporous Silica: Aerobic Oxidation of Benzyl Alcohols/Benzaldehydes and Reduction of Nitroarenes

Catalysis Surveys from Asia - 2-(2-Pyridyl)benzimidazole (PyBzIm) was supported onto magnetic mesoporous silica, Fe3O4@SiO2@SBA-15 via the click chemistry. The supported ligand was treated with...     

Theoretical investigation of triazine based a star shape pyrrole monomer

In this work, we report a comprehensive theoretical investigation of electroactive star shaped pyrrole functionalized triazine monomer with two main goals. First goal of this work is to explore the physical and chemical properties of the monomer, then to investigate correlation between the experimental and the theoretical properties of monomer. The scale factor which is calculated from B3LYP/cc-pVDZ was determined as 0.985 for FT-IR and it is an important and reliable contribution to the literature. It is determined that the most appropriate basis set for this molecule. The other novel objective of this research is to investigate temperature effect on displacement of chlorine atoms in 2,4,6-trichloro-1,3,5-triazine. This method applied for the first time in the literature for triazines is especially crucial to the synthesis of unsymmetrical triazines.     

Loganin Alleviates Gout Inflammation by Suppressing NLRP3 Inflammasome Activation and Mitochondrial Damage

Gout is a type of inflammatory arthritis caused by the deposition of monosodium uric acid (MSU) crystals in tissues. The etiology of gout is directly linked to the NLRP3 inflammasome, since MSU crystals are NLRP3 inflammasome activators. Therefore, we decided to search for a small-molecule inhibitor of the NLRP3 inflammasome for the prevention of gout inflammation. We found that loganin suppressed MSU crystals-induced caspase-1 (p20) and interleukin (IL)-1β production and apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) specks formation in mouse primary macrophages, showing its ability to inhibit the NLRP3 inflammasome. In an air pouch inflammation model, oral administration of loganin to mice prevented MSU crystals-induced production of mature IL-1β and IL-18 in air pouch exudates, resulting in decreased neutrophil recruitment. Furthermore, oral administration of loganin suppressed MSU crystals-induced gout inflammation in a mouse foot gout model, which was accompanied by the inhibition of the NLRP3 inflammasome. Loganin blocked de novo synthesis of mitochondrial DNA in air pouches and foot tissues injected with MSU crystals. Consistently, loganin prevented MSU crystals-induced mitochondrial damage in macrophages, as it increased mitochondrial membrane potential and decreased the amount of mitochondrial reactive oxygen species. These data demonstrate that loganin suppresses NLRP3 inflammasome activation by inhibiting mitochondrial stress. These results suggest a novel pharmacological strategy to prevent gout inflammation by blocking NLRP3 inflammasome activation and mitochondrial dysfunction.     

Natural convection in rectangular enclosures with partial heating and cooling

The flow and heat transfer in partially heated and partially cooled cavities were numerically analyzed. Using the control volume approach, a computer program based on SIMPLE algorithm was developed. A square enclosure with variable size heater and cooler on the vertical walls was considered. Computations were carried out to investigate the effects of heater and cooler size on the heat transfer rate. It was observed that for a given cooler size, the mean Nusselt number decreases with increasing heater size. On the other hand, for a given heater size, the mean Nusselt number increases with increasing cooler size. For all Rayleigh numbers considered, the same behavior was observed.

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Natürliche Konvektion in geschlossenen Räumen mit partieller Heizung und Kühlung der Wände

Zusammenfassung Es wurde ein numerisches Modell zur Analyse des Strömungs- und Wärmeübergangsverhaltens in teilweise beheizten und gekühlten Hohlräumen entwickelt und unter Verwendung des Kontrollvolumenprinzips und des Algorithmus SIMPLE als Computer-Programm formuliert. Der Hohlraum ist rechteckig und die variablen Heiz- und Kühlflächen befinden sich auf gegenüberliegenden Vertikalseiten. Hauptziel der Berechnungen war es, den Einfluß der variablen Heiz- und Kühlflächen auf den Wärmeübergang zu ermitteln. Für eine bestimmte Kühlergröße zeigte sich eine Abnahme der gemittelten Nußelt-Zahl mit zunehmender Heizfläche. Andererseits — bei gegebener Heizfläche — stieg die Nußelt-Zahl mit der Kühlfläche an. Dieses Verhalten wurde bei allen untersuchten Rayleighzahlen gefunden.

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Nomenclature g gravitational acceleration - H height of cavity - k thermal conductivity of fluid - l _C cooler size - l _H heater size - mean Nusselt number - Nu _y local Nusselt number - P pressure - Pr Prandtl number - Ra Rayleigh number (Ra = gH ³(T _H –T _C)/()) - T temperature - T _C temperature of cold surface - T _H temperature of hot surface - T _R reference temperature (T _R = (T _C +T _H)/2) - u velocity component inx-direction - x horizontal axis - v velocity component iny-direction - y vertical axis Greek symbols thermal diffusivity - thermal expansion coefficient - density of fluid - stream function - kinematic viscosity     

On the dynamic snap-out instability of inflated non-linear spherical membranes

The dynamic behavior of a spherical membrane, made of Mooney material and subjected to a uniform inflating step-pressure, is studied. Its phase-planes and nondimensional radius versus time curves are plotted for different values of the material constants. The conditions for dynamic snapout instability are discussed. The relations between the static behavior of the membrane and the dynamic instability are pointed out.     

Heat transfer in an oscillating vertical annular liquid column open to atmosphere

The heat transfer from a surface heated with constant heat flux to an oscillating vertical annular liquid column having an interface with the atmosphere is investigated experimentally in the present paper. The analysis is carried out for the case of different oscillation frequencies while the displacement amplitude remains constant. Based on the experimental data a correlation equation is obtained for the cycle-averaged Nusselt number as a function of kinetic Reynolds number.     

Sonochemical synthesis and electrochemical characterization of α-nickel hydroxide: precursor effects

Sonochemical degradation of urea was employed to synthesize alpha-nickel hydroxide from different nickel salts. Utilization of ultrasound yielded products with properties significantly different than the products obtained by thermal degradation of urea. The effect of intercalating chloride, nitrate, acetate, and sulfate anions on morphology and electrochemical performance was studied. The sulfate-intercalated sample had the smallest interlayer spacing when obtained by the sonochemical method, contradicting all the previous thermal synthesis results. The specific capacitance trend also differed from the literature values, and the value for the sulfate-intercalated sample was larger than that of acetate- and nitrate-intercalated samples. Ultrasonic synthesis increased the specific capacitance of the sulfate-intercalated sample significantly. This sample was also the most reversible and had the highest charge efficiency.