Photoconductivity,Antioxidant, and Antimicrobial Activities of Some Acenaphthenequinone Derivatives

Russian Journal of General Chemistry - Photoconductive acenaphthenequinone derivatives have been synthesized by a one-pot process of acenaphthenequinone with different aromatic hydrazides...     

PRESSURE-VELOCITY EQUILIBRIUM HYDRODYNAMIC MODELS

This article describes mathematical models for phase separated mixtures of materials that are in pressure and velocity equilibrium but not necessarily temperature equilibrium. General conditions for constitutive models for such mixtures that exhibit a single mixture sound speed are discussed and specific examples are described.     

Synthesis and Antiproliferative and Antilipolytic Activities of a Series of 1,3- and 1,4-Bis[5-(R-sulfanyl)-1,2,4-triazol-3-yl)benzenes

Russian Journal of Organic Chemistry - A series of 1,3 and 1,4-bis[5-(R-sulfanyl)-1,2,4-triazol-3-yl)benzene derivatives were synthesized by the reaction of isophthalic and terephthalic acid...     

Crystal structure of cis-[Rh(biq)2Cl2]Cl·3H2O: Solid-state characterization and crystal packing analysis

The title compound, cis-[Rh(biq)₂Cl₂]Cl·3H₂O (biq = 2,2′-biquinoline) crystallized in the monoclinic space group P2 ₁ /n with a = 11.231(2) Å, b = 20.895(4) Å, c = 14.081(3) Å, β = 94.76(3)°, V = 3293.0(11) ų, D _c = 1.565 g cm⁻³, μ = 0.806 mm⁻¹, F(000) = 1576 and Z = 4. It contains a monomeric [Rh(biq)₂Cl₂]⁺ cation, a chloride ion and three molecules of H₂O. The rhodium(III) ion is hexa coordinated forming a distorted octahedral arrangement. The mean Rh(III)–N distance for the four Rh(III)–N bonds is 2.0625 Å. The two chloride atoms are bonded in a cis configuration [Rh(III)–Cl bond distances are 2.329(3) and 2.341(4) Å]. The structure shows a curling stacks of cationic complexes interacting via offset-face-to-face (OFF) π–π aryl interaction motif. Water molecules and chloride ions are hydrogen bonded (H₂O···H–OH and Cl···H–OH) and links the curling stacks by hydrogen bonding via Rh–Cl···H–OH interactions.     

Correlation between biological activity and energies of electronic transitions in benzodiazepines. Negative ion mass spectrometry and ultraviolet absorption spectroscopy study of some derivatives

A correlation between the energies of electronic singlet transitions in benzodiazepines and their biological activity, which was revealed earlier by means of negative ion mass spectrometry with resonance electron capture, has been verified with a UV absorption spectroscopy investigation. Also, it has been noted that the energies of electronic singlet transitions in benzodiazepines are close in value to the ionization energies of atoms Cs, Rb, K, Na, Li and Tl, the cations of which are known to play an important role in nerve cell excitation processes. Copyright 1999 John Wiley & Sons, Ltd.     

Gas-phase deprotonation of arylalkylamines. A collision-induced dissociation study

The collision-induced dissociation (CID) of deprotonated arylalkylamines of general formula R(1)C(6)H(4)CHR(2)CH(2)NR(3)(2) (where R(1) = H, OH, F or NO(2); R(2) = H or OH; R(3) = H or CH(3)) generated by negative chemical ionization with H(2)O and D(2)O as ionizing reagents, is discussed. The negative chemical ionization mass spectra show that, in the absence of a hydroxy group in the aromatic ring, deprotonation takes place at the benzylic position whereas the proton is lost from the OH group when present. The nitro compound forms only M(-.) ions. The CID spectra of the deprotonated molecules show that fragmentations are strongly dependent on the structural features of the molecules, namely the presence or absence of substituents in the aromatic ring or aliphatic chain. Copyright 1999 John Wiley & Sons, Ltd.     

Altholactone displays promising antimicrobial activity

The antimicrobial activity of altholactone, a naturally extracted styryllactone isolated from Goniothalamus malayanus, was determined against Gram positive (S. aureus ATTC 25923, S. aureus ATTC 25392, and E. faecalis ATTC 29212) and Gram negative (E. coli ATTC 35218, S. typhi ATTC 14023 and P. aeruginosa ATCC 27853) reference bacteria and against the fungus C. albicans ATTC 10231. Different concentrations of altholactone (0, 12, 25, and 50 μg/mL) were used. Results revealed that altholactone inhibited the growth of all tested microbes except P. aeruginosa ATCC 27853 in a dose-dependent manner, with the highest cytotoxic effects occurring at 50 μg/mL. The average of the inhibition zones of the different concentrations was between 0-30 mm. Furthermore, altholactone-induced antimicrobial activity against the more sensitive microbes was assessed by measuring the minimal inhibitory concentration (MIC). Results indicated that Gram positive (S. aureus ATTC 25923, S. aureus ATTC 25392, and E. faecalis ATTC 29212) cells were more sensitive to altholactone than Gram negative ones (E. coli ATTC 35218, S. typhi ATTC 14023). C. albicans showed moderate sensitivity. These results indicate that altholactone might be a potential antimicrobial agent, particularly in ciprofloxacin-refractory S. aureus and E. faecalis infections. Further investigations are required to illustrate the mechanism(s) by which altholactone produces its antimicrobial effects.     

Purification and Characterization of Agarase from Marine Bacteria <Emphasis Type="Italic">Acinetobacter</Emphasis> sp. PS12B and Its Use for Preparing Bioactive Hydrolysate from Agarophyte Red Seaweed <Emphasis Type="Italic">Gracilaria verrucosa</Emphasis>

Acinetobacter strain PS12B was isolated from marine sediment and was found to be a good candidate to degrade agar and produce agarase enzyme. The extracellular agarase enzyme from strain PS12B was purified by ammonium sulfate precipitation followed by DEAE-cellulose ion-exchange chromatography. The specific activity of the crude enzyme which was 1.52 U increased to 45.76 U, after two-stage purification, with an enzyme yield of 9.76%. Purified enzyme had a molecular mass of 24 kDa. The optimum pH and temperature for activity of purified agarase were found to be 8.0 and 40 °C, respectively. The K_m and V_max values for agarase were 4.69 mg/ml and 0.5 μmol/min, respectively. Treatment with EDTA reduced the agarase activity by 58% at 5 mM concentration. The enzyme activity was stimulated by the presence of Fe²⁺, Mn²⁺, and Ca2⁺ ions while reducing reagents (β-mercaptoethanol and dithiothreitol, DTT) enhanced its activity by 30–40%. The purified agarase exhibited tolerance to both detergents and organic solvents. Major hydrolysis products of agar were DP4 and also a mixture of longer oligosaccharides DP6 and DP7. The enzyme hydrolysed seaweed (Gracilaria verrucosa) exhibited strong antioxidant activity in vitro. Successful hydrolysis of seaweed indicates the potential use of the enzyme to produce seaweed hydrolysate having health benefits as well as the industrial application like the production of biofuels.     

Computer extended series solution for unsteady flow in a contracting or expanding pipe

Unsteady flow in a semi-infinite contracting or expanding pipeis reinvestigated using long series analysis. The proposed seriesmethod is useful in analysing the problem for a moderately largeconstant ( = aa/, where a = a(t), the radius of the pipe isa function of time, a(t) is the velocity of the wall, and iskinematic viscosity). For positive values of (expansion ofthe pipe) accuracy of the series representing shear stress andpressure gradient is increased from = 2.89 to = 6.0 by extractingthe singularity followed by completion of the series. For negativevalues of (contraction of the pipe), we revert the series whichresults into the increase of the region of validity of the transposedseries from = -25.0 to = -2.89. Later we use Padé approximantsfor summing them. Also, the asymptotic solution for large valuesof is obtained and it agrees closely with pure numerical valuesof shear stress at the wall and pressure gradient.