Quantum ergodicity in small molecules: The continuum fluorescence of nitrogen dioxide

The failure of selection rules on K_a, v, and vibronic symmetry in the visible band systems of NO₂ are interpreted as resulting from the coupling of the excited electronic state with vibrational levels of the ground electronic state which are above the threshold for ergodic motion and therefore retain no quantization of those observables. This failure is shown to lead directly to the anomalous continuum fluorescence of NO₂, and is intimately related to the anomalous lengthening of the radiative lifetime of the excited state (the Douglas effect). It is predicted that most molecules which exhibit anomalous lifetime lengthening will also exhibit anomalous selection rules and, consequently, anomalous continuum emission.     

Semileptonic decays of charmedD ± meson

Using the ACCMOR spectrometer equipped with a vertex telescope of high resolution silicon microstrip detectors 74 decays \(D^ + \to \bar K^{*0} (892)e^ + v_e \) (andcc.) withx _F <0.4 have been observed in 200 GeV π^? Be interactions. The cross-section forD ^± production, itsx _F -dependence in the central region and theD ^± lifetime have been measured.     

Hadronic ϕ production and the lund model for lowp T interactions

Experimental results on inclusive ? production are compared with the Lund model for lowp _T hadronic interactions. The data is based on a sample of 600,000 ? mesons in the kinematic rangep _T <1.0 (GeV/c)² and 0.0<x _F<0.4, produced in π^±,K ^±,p and \(\bar p\) Be interactions at 100 GeV/c and 120 GeV/c incident momentum. The Lund model reproduces the shapes of the longitudinal differential cross sections reasonably well, but the relative cross sections for incident, π,K andp show a discrepancy with the data.     

Separation, identification and quantification of riboflavin and its photoproducts in blood products using high-performance liquid chromatography with fluorescence detection: a method to support pathogen reduction technology

A medical device using riboflavin (RB) and light is being developed for the reduction of pathogens in platelet concentrates (MIRASOL pathogen reduction technology [PRT]). A high-performance liquid chromatography (HPLC) method for the quantification of RB and its main photoproduct, lumichrome (LC) in blood components has been developed and validated. In addition, the same method has been used to identify and quantify the presence of additional photoproducts-catabolites of RB. Levels of these agents before and after treatment as well as endogenous levels present in normal donor blood are reported using this analytical technique. The method allows for quantitative and qualitative analysis of RB and LC in blood components using HPLC-fluorescence detection, a Zorbax SB-CN (stable bond cyano) column and a methanol-water mobile phase. Quantitation and qualitative analysis of additional photoproducts of RB was also performed, but the method has not been validated for these other components. The method described has passed an 8 day validation and has been found to be adequate for its intended use. The range of the method for RB is 0.016-1.500 microM and for LC is 0.060-1.500 microM. The method detection limit for RB is 0.0006 microM and for LC is 0.012 microM. The acceptance criteria for repeatability were met; the relative standard deviation for RB was 0.64% and for LC was 0.76%. The acceptance criteria for bias were met with a 97% average recovery for RB and a 102% recovery for LC. Samples were centrifuged and diluted 1:50 with 0.9% saline before analysis. No protein precipitation or extraction was required. A mass balance of approximately 93.4-94.4% was achieved after exposure of products to UV light in the intended pathogen reduction treatment method. The method permitted the identification of photoproducts in blood that were both naturally occurring and produced after photolysis of blood samples treated with the PRT process. The identity of these photoproducts has been established using HPLC Tandem Mass Spectrometry (MS/MS) and UV spectroscopic methods and has been correlated with known metabolites and catabolites of RB. HPLC with fluorescence detection using a reverse phase cyano-column allows for accurate separation, identification and quantification of both RB and LC in blood products without the need for solvent extraction or protein precipitation. Additional photoproducts could also be identified and quantified using this method. The presence of these agents in normal, untreated blood suggests that their presence in blood is ubiquitous.     

Polyfluorobicyclo(2,2,1)heptanes Part VIII. Bis(undecafluorobicyclo(2,2,1)heptan-1-yl)- and bis(4H-decafluorobicyclo(2,2,1)heptan-1-yl)-mercury

The title compounds were prepared from 1-lithio-undecafluorobicylco(2,2,1)-heptane, and from 1H,4-lithio-decafluorobicyclo(2,2,1)heptane and 1H-decafluorobicyclo(2,2,1)hept-4-yl magnesium iodide with mercuric chloride. With sulphur and caesium fluoride in dimethyl formamide, both mercurials gave the corresponding thioxides and these on hydrolysis gave the known bridgehead thiols. With sulphur alone, the undecafluoro mercurial gave mainly the disulphide and a range of polysulphides, under conditions which left the 4H-decafluoro mercurial unchanged. Conventional d.c. polarography of the mercurials indicated an inconsistency in the use of this method for determining the acidities of highly fluorinated hydrocarbons.     

High-capacity method for purification of human liver hexosaminidase B using hydrophobic chromatography

Hydrophobic chromatography was investigated as a purification procedure for human liver hexosaminidases. Both phenyl-Sepharose and valine-Sepharose have a high binding capacity for hexosaminidases. A degree of resolution between the A and B isozymes is achieved with phenyl-Sepharose.Both hydrophobic supports myst be used close to their capacity in order to recover the applied enzyme.Two purification procedures for human liver hexosaminidase B were employed, which resulted in recoveries of approximately 48 and 24% with final specific activities of 33,400 and 4840 nmole/min·mg, respectively.     

On some nonself mappings

Let X be a Banach space, let K be a non–empty closed subset of X and let T : K → X be a non–self mapping. The main result of this paper is that if T satisfies the contractive–type condition (1.1) below and maps ?K (?K the boundary of K) into K then T has a unique fixed point in K.     

Kinetics of the metathetical reaction between carbon tetrachloride and toluene

A metathetical reaction between carbon tetrachloride and toluene to give benzyl chloride and chloroform occurs at temperatures above 200°C (k = 4.8 × 10¹⁰ e^?32,900/RT cc mole^?1sec^?1). The reaction does not involve free radicals, as is shown by the kinetic behavior of the system, by the lack of effect of added free-radical chain inhibitors, and by the absence of the expected chain termination product, hexachloroethane. The reaction is one of a general type between carbon tetrachloride and alkanes or alkylaromatics, but at the temperatures required it is often obscured by dehydrohalogenation of the product to the highly reactive olefin. At high temperatures, benzyl chloride reacts with toluene to give bibenzyl and hydrogen chloride, apparently also by a metathetical reaction. The transition state is postulated to be four-center, in which the carbon-chlorine and carbon–hydrogen bonds are broken and reformed: The experimental preexponential factor is in good agreement with that calculated from transition-state theory.     

Laser-excited fluorescence of CSCl2

Resonance fluorescence spectra of the $\text{A}\text{?}{}^1\text{A}{}_2\text{→}\text{X}\text{?}{}^1\text{A}{}_1$ system of CSCl₂ are excited by an Ar⁺ laser operated at 5145 Å. The radiation is selectively absorbed by the 2₀¹3₀¹4₀¹ transition of the ³⁵Cl₂CS isotope. About 55 fluorescence bands have been measured and assigned, and the vibrational constants of the ground state have been calculated from the observed displacements.