Compact beam expander based on planar structure to avoid inner focus

Optical Review - Based on the planar optical theory, compact beam expanders are proposed to miniaturize the dimension of an optical system. Both simulated and experimental results have demonstrated...     

Experimental Study of Pulse Polarity and Magnetic Field on Ozone Production of the Dielectric Barrier Discharge in Air

We studied the combined effect of the pulse or sinusoidal driving voltage and magnetic field on electrical characteristics and ozone production of a dielectric barrier discharge in air. These effects were studied for both polarities of the pulse. We found that the pulse polarity, as well as the magnetic field, affects discharge ozone production only for higher powers. The discharge driven by sinusoidal voltage produces higher ozone concentration than the discharge driven by voltage pulses of negative polarity. The discharge driven by the voltage pulses of negative polarity produces higher ozone concentrations than the discharge driven by positive voltage pulses. Ozone production yield for the voltage pulses of negative polarity is similar to that of sinusoidal driving voltage. For the positive polarity of voltage pulses, the yield is lower. Magnetic field slightly increases the concentration of ozone produced by the discharge and ozone production yield only for the discharge driven by positive voltage pulses. For the discharge driven by the sinusoidal voltage or by the pulses of the negative polarity magnetic field has only small effect on the concentration of ozone produced by the discharge.     

Air Supply Mode Effects on Ozone Production of Surface Dielectric Barrier Discharge in a Cylindrical Configuration

Plasma Chemistry and Plasma Processing - We investigated the air supply mode effects on ozone production of the surface dielectric barrier discharge in the cylindrical configuration. The air into...     

Protonation and bromination of an osmabenzyne: reactions leading to the formation of new metallabenzynes

The reactivities of benzynes and metal-carbyne complexes are normally associated with the triple bond units. However, we have now found that electrophiles do not attack the formal osmium-carbon triple bond of osmabenzyne complex 1. Instead, 1 undergoes electrophilic substitution reactions-the typical reactions of aromatic systems.     

The interfacial conformation of polypropylene glycols and foam behaviour

The foam behaviour of low molecular weight polypropylene glycols (PPG) was investigated as a function of concentration and molecular weight (190–2000 g mol⁻¹). For each polypropylene glycol, foam stability increases with concentration and passes through a maximum, beyond which foamability is suppressed as the solubility limit of the glycol is exceeded and droplets of glycol form. Light-scattering data as well as static and dynamic surface tension results provide the key information leading to these interpretations. A maximum in foamability was observed for the PPG molecules with increasing molecular weight (caused by a change in molecular conformation at the interface). This suppresses the Marangoni effect and leads to a decrease in foam stability.     

Head-to-tail dimerization and organogelating properties of click peptidomimetics

Click triazole-based oligopeptides 1-3 were found to self-dimerize (K(dim) ≈ 10-680 M(-1)) in a head-to-tail fashion based on (1)H variable concentration, 2D, and H/D exchange NMR, VPO, CD, FT-IR studies and Gaussian 03 simulations. The dimerization constant K(dim) was shown to increase with increasing number of the amino acid units. Within the same oligomeric series, the K(dim) value is strongly affected by the size of the C-terminal end group. The tripeptides 2 are also excellent organogelators of aromatic solvents.     

Transient resonance Raman and density functional theory investigation of the chlorine atom/carbon disulfide molecular complex involved in selective alkane photochlorination reactions

The structure and bonding of the chlorine atom/carbon disulfide (CS(2)/Cl) complex involved in selective photochlorination reactions with alkanes was directly probed using transient resonance Raman spectroscopy. The experimental Raman vibrational frequencies were compared to those computed from density functional theory calculations for probable structures of the CS(2)/Cl complex. Our results indicate that the S [double bond] C [double bond] S...Cl complex species is responsible for the approximately 370 nm transient absorption band observed after ultraviolet photolysis of CCl(4) in the presence of CS(2). We discuss the structure and properties of the S [double bond] C [double bond] S...Cl complex and compare them with those for the related benzene/Cl and pyridine/Cl complexes.     

A multipolymer system for organocatalytic alcohol oxidation

A system involving two polymer-supported reagents for the selective and organocatalytic oxidation of alcohols to aldehydes or ketones has been developed in which both polymeric reagents can be recovered and reused.     

Effect of adenine on bacterial translocation using technetium-99m labeled E. coli in an intestinal obstruction model in rats

This study aims to investigate effects of adenine on bacterial translocation (BT) using ^99mTc-labeled E. coli in an intestinal obstruction rat model. In the study twenty-one rats were used. The rats were divided into three groups according to different feeding patterns. The control group (CG) was fed with a standard chow diet for 7 days. Group A1 and group A2 were fed with adenine supplemented chow diet for 7 days. At the end of the feeding period, after all groups was submitted intestinal obstruction. ^99mTc-E. coli was injected into the rats’ terminal ileum under anesthetic. The rats were sacrificed under aseptic conditions at 24th h after the surgery. The uptake of ^99mTc-E. coli was determined in organs such as the liver, mesenteric lymph nodes, spleen and ileum. Group A1 and group A2 results show that the uptake of ^99mTc-E. coli decreased in the blood and organs comparing to the CG. As a result, it was observed that adenine reduced the level of BT when compared with CG. The beneficial effect of adenine on BT in intestinal obstruction was observed. However, further studies are needed to more clearly assess how this benefit can be achieved.