The letter “s” (and the sQGP)

Data from the Relativistic Heavy Ion Collider over the last five years have led many to conclude that the medium created is not the expected quark–gluon plasma (QGP), but rather a strongly coupled or strongly interacting quark–gluon plasma (sQGP). We explore the meaning of this possible paradigm shift and the experimental and theoretical arguments that are associated with it. In this proceedings we detail only a small subset of the relevant issues as discussed at the Hot Quarks 2006 Workshop. PACS 25.75.-q; 25.75.Nq     

Measurement of the inhibitory potential and detoxification of biomass pretreatment hydrolysate for ethanol production

Applied Biochemistry and Biotechnology - The Microtox assay represents a rapid, accurate, and reproducible method for determining general microbial toxicity. This assay was used to evaluate the...     

EFFECT OF PHOTOSELECTION UPON SATURATION AND THE DICHROIC RATIO IN FLASH EXPERIMENTS UPON EFFECTIVELY IMMOBILIZED SYSTEMS

Abstract— Flash spectroscopy of photochemical or photobiological systems, such as bacteriorhodopsin in purple membrane, for which the chromophore transition dipole moment does not undergo complete reorientation during the time of the flash, is considered as a function of light intensity. Due to photoselection, saturation proceeds very slowly with increasing flash intensity and the linear dichroic ratio decays rapidly from a maximum of three at zero flash intensity. Simple formulae are derived to describe these effects under stringent assumptions. Calculations are also performed which relax the assumptions by taking into account (i) non-zero optical density, (ii) thermal decay of the photoproduct during the flash and (iii) non-zero angle y between the initial chromophore and its photoproduct. Agreement with experiments on bacteriorhodopsin in purple membranes is excellent.     

Conversion of distiller's grain into fuel alcohol and a higher-value animal feed by dilute-acid pretreatment

Over the past three decades ethanol production in the United States has increased more than 10-fold, to approx 2.9 billion gal/yr (mid-2003), with ethanol production expected to reach 5 billion gal/yr by 2005. The simultaneous coproduction of 7 million t/yr of distiller's grain (DG) may potentially drive down the price of DG as a cattle feed supplement. The sale of residual DG for animal feed is an important part of corn dry-grind ethanol production economics; therefore, dry-grind ethanol producers are seeking ways to improve the quality of DG to increase market penetration and help stabilize prices. One possible improvement is to increase the protein content of DG by converting the residual starch and fiber into ethanol. We have developed methods for steam explosion, SO₂, and dilute-sulfuric acid pretreatment of DG for evaluation as a feedstock for ethanol production. The highest soluble sugar yields (∼77% of available carbohydrate) were obtained by pretreatment of DG at 140°C for 20 min with 3.27 wt% H₂SO₄. Fermentation protocols for pretreated DG were developed at the bench scale and scaled to a working volume of 809 L for production of hydrolyzed distiller's grain (HDG) for feeding trials. The pretreated DG was fermented with Saccharomyces cerevisiae D₅A, with ethanol yields of 73% of theoretical from available glucans. The HDG was air-dried and used for turkey-feeding trials. The inclusion of HDG into turkey poult (as a model non-ruminant animal) diets at 5 and 10% levels, replacing corn and soybean meal, showed weight gains in the birds similar to controls, whereas 15 and 20% inclusion levels showed slight decreases (−6%) in weight gain. At the conclusion of the trial, no negative effects on internal organs or morphology, and no mortality among the poults, was found. The high protein levels (58–61%) available in HDG show promising economics for incorporation of this process into corn dry-grind ethanol plants.     

A microfluidic system for high-speed reproducible DNA sizing and quantitation

Microfabrication technology was used to develop a system consisting of disposable glass chips containing etched channels, reagents including polymer matrix and size standards, computer-controlled instrumentation for performing electrophoretic separations and fluorescence detection of double-stranded DNA, and software for automated data analysis. System performance was validated for separation and quantitation reproducibility using samples varying in amount and size of DNA fragments, buffer composition, and salt concentrations. Several applications of the microfluidic system for DNA analysis have been demonstrated, such as of polymerase chain reaction (PCR) products, sizing of plasmid digests, and detection of point mutations by restriction fragment length polymorphism (RFLP) mapping.     

Multiple emissions from charge transfer excited states of ruthenium(II)—polypyridine complexes

The complex cis-[(bpy)₂Ru

₂]⁴⁺ (bpy is 2,2′-bipyridine) has been prepared by methylation of (bpy)₂Ru

₂]²⁺. Electrochemical studies show that introduction of the bound pyridinium group creates a chemically attached electron acceptor site (E_1/2 = ?0.76 V in 0.1 M [N(n-C₄H₉)₄]PF₆-acetonitrile versus the SSCE). Evidence for a low-lying dπ — π^*

charge transfer (CT) state has been obtained by the appearance of a low energy emission at λ_max 680 nm in ecetonitrile (τ₀ = 104 ns) and for an upper dπ — π^* (bpy) state by a higher energy emission at 580 nm in a methanol glass at 77 K (τ₀ = 7.59 μs). Both emissions appear in a water—ethylene glycol solution containing 5% by weight polyvinyl alcohol at room temperature.     

Intraligand charge transfer in the Pd(II) oxinate complex Pd(qol)2. Site-selective emission, excitation, and optically detected magnetic resonance

The first spectroscopic investigation of Pd(qol)2 (qol- = 8-quinolinolato-N,O = oxinate) dissolved in an n-octane matrix (Shpol'skii matrix) is reported. Application of several spectroscopic methods at liquid helium temperatures (typically, T = 1.2 K), such as site-selective and highly resolved luminescence and excitation spectroscopy, time-resolved emission spectroscopy, optically detected magnetic resonance, microwave recovery, phosphorescence microwave double-resonance, and magnetic fields, allows us to characterize the lowest excited electronic states in detail. In accord with previous assignments for the related Pt(qol)2 it is shown that these lowest states represent-intraligand charge-transfer states, namely, 1ILCT and 3ILCT. The electronic origin of the 1ILCT state lies at 20,617 cm(-1) (site A). It exhibits a nearly homogeneous line width with a half-width of about 80 cm(-1) (fwhm), which corresponds to a lifetime of tau(1ILCT) approximately equals 2 x 10(-13) s. This value is even shorter than that found for Pt(qol)2, presumably due to intersystem crossings and relaxations to dd* states. The electronic origin of the 3ILCT state lies at 16 090 cm(-1) (site A), and its zero-field splittings (zfs) into three sublevels are 2E = 2356 MHz (0.0785 cm(-1)) and D - E = 5241 MHz (0.175 cm(-1)). The emission decay times of the three sublevels are determined as tauI = 90 +/- 30 ms, tau(II) = 180 +/- 10 mus, and tau(II) = 80 +/- 10 mus. (Slightly different values are found for a second site B at 16,167 cm(-1).) From the small values of zfs and the long emission decay times it is concluded that metal-d or MLCT admixtures to 3ILCT are very small. This result clearly reflects the ligand-centered character of the transition. The assignment as an ILCT transition is supported by the occurrence of relatively strong vibrational satellites of Pd-N and Pd-O character in highly resolved emission spectra. Although the transition is ascribed to a charge-transfer process, the geometry changes between the ground state and 3ILCT are very small. The results found for Pd(qol)2 are compared to those of companion studies of Pt(qol)2 and Pt(qtl)2 (qtl- = 8-quinolinethiolato-N,S).     

5.2-5.6-microm source tunable by frequency conversion in a GaAs-based waveguide

A tunable mid-IR source obtained by difference-frequency generation is demonstrated in a selectively oxidized GaAsAlAs multilayer waveguide. We designed the waveguide to present the required form birefringence for phase matching of the nonlinear interaction. We took special care to lower losses for the mid-IR radiation. IR tunability from 5.2 to 5.6 mum was achieved by variation of the waveguide temperature and one pump wavelength. IR output power as great as 0.12 muW was obtained with the product of two pump powers of 7 mW(2). Losses of ~50 cm(-1) were measured for the mid-IR radiation. These losses are attributed to surface scattering.