Synthesis of 2,4-Heptadiene

2,4-Heptadiene can exist in four isomeric cis-trans forms; a fact which probably accounts for the different physical constants reported in the literature. The present synthesis involved a high temperature pyrolysis as the final step, in the hope that only one isomer would be formed under these conditions

Spectral fluctuation properties of spherical nuclei

The spectral fluctuation properties of spherical nuclei are considered by use of NNSD statistic. With employing a generalized Brody distribution included Poisson, GOE and GUE limits and also MLE technique, the chaoticity parameters are estimated for sequences prepared by all the available empirical data. The ML-based estimated values and also KLD measures propose a non regular dynamic. Also, spherical odd-mass nuclei in the mass region, exhibit a slight deviation to the GUE spectral statistics rather than the GOE.Comment: 10 pages, 2 figure

Synthesis of 4-Piperidinoflavan

A study of the reaction of flavylium perchlorate with piperidine showed that piperidine perchlorate was formed plus two other compounds. One of these appears to be 4-piperidinoflavene which should be reducible to 4-piperidinoflavan. This compound had not been described previously, hence its synthesis was undertaken. Flavanone was prepared according to the method of Kostanecki (1). Catalytic reduction of flavanone with hydrogen and a platinum catalyst gave a 79% yield of a compound melting at 145- 147°. This corresponds to the, B-isomer of 4-hydroxyflavan originally obtained by Karrar, Yen and Reichstein (2) as the result of a titanous chloride reduction of flavanone. Mozingo and Adkins (3) also obtained this ,B-isomer by catalytic reduction of flavanone but used copper-chromium oxide at 120° and hydrogen at 100-200 atm. Treatment of the 4-hydroxyflavan with phosphorus tribromide at 0° gave a 52% yield of 4-bromoflavan. An ether solution of this bromo-compound reacted with two equivalents of piperidine to form piperidinium hydrobromide and {3-4 piperidinoflavan. Upon recrystallization from ether, colorless needles were obtained melting at 137-138° which had the correct analysis for this compound

Exploratory Studies on the Constituents of Scoparia dulcis (Linn)

In 1942 M. C. Nath of the University of Dacca in India reported that an Indian drug called amellin was effective orally in treating diabetes (1). From 1942-1947, seven additional papers have been published by Nath and co-workers (2) which describe the physiological effects of amellin and also clinical results on 15 patients. It is stated that oral doses of 15 to 20 mg. per day along with calcium salts over a period of several weeks to three months cause return of blood sugar to normal levels and disappearance of glycosuria and ketonuria. The only information about amellin given, was that it was obtained from a plant Scoparia dulcis (Linn) and that it was not an alkaloid. No details of extraction, isolation or composition were published. The object of the present work was to explore the possibility of obtaining physiologically active extracts of this plant

Shedding Light on Avian Influenza H4N6 Infection in Mallards: Modes of Transmission and Implications for Surveillance

Background: Wild mallards (Anas platyrhychos) are considered one of the primary reservoir species for avian influenza viruses (AIV). Because AIV circulating in wild birds pose an indirect threat to agriculture and human health, understanding the ecology of AIV and developing risk assessments and surveillance systems for prevention of disease is critical. Methodology/Principal Findings: In this study, mallards were experimentally infected with an H4N6 subtype of AIV by oral inoculation or contact with an H4N6 contaminated water source. Cloacal swabs, oropharyngeal swabs, fecal samples, and water samples were collected daily and tested by real-time RT-PCR (RRT-PCR) for estimation of viral shedding. Fecal samples had significantly higher virus concentrations than oropharyngeal or cloacal swabs and 6 month old ducks shed significantly more viral RNA than 3 month old ducks regardless of sample type. Use of a water source contaminated by AIV infected mallards, was sufficient to transmit virus to naïve mallards, which shed AIV at higher or similar levels as orally-inoculated ducks. Conclusions: Bodies of water could serve as a transmission pathway for AIV in waterfowl. For AIV surveillance purposes, water samples and fecal samples appear to be excellent alternatives or additions to cloacal and oropharyngeal swabbing. Furthermore, duck age (even within hatch-year birds) may be important when interpreting viral shedding results from experimental infections or surveillance. Differential shedding among hatch-year mallards could affect prevalence estimates, modeling of AIV spread, and subsequent risk assessments

Reactivity of the Halogen in the Isomeric 4- and 4\u27-Chloroazoxybenzenes

The relative ease of displacement of a halogen in the benzene ring by anionic reagents is markedly influenced by the character of other substituents in the ring. A thorough survey of the literature on these aromatic nucleophilic substitution reactions has been given by Bunnett and Zahler (1). These authors discuss the influences exerted by various groups in the ortho, meta and para positions, the effects of different electron donor reagents and variations in experimental conditions. Since no data are available concerning the effect of the azoxy group, it was desirable to synthesize some chloro-substituted aromatic azoxy compounds and compare them with chloro-nitro-compounds and chloro-azo-compounds. The azo-grouping has only a slight activating effect (2) being reported by Badger, Cook and Vidal (3) to be about one-sixth as effective as a nitro group

Direct reaction measurements with a 132Sn radioactive ion beam

The (d,p) neutron transfer and (d,d) elastic scattering reactions were measured in inverse kinematics using a radioactive ion beam of 132Sn at 630 MeV. The elastic scattering data were taken in a region where Rutherford scattering dominated the reaction, and nuclear effects account for less than 8% of the cross section. The magnitude of the nuclear effects was found to be independent of the optical potential used, allowing the transfer data to be normalized in a reliable manner. The neutron-transfer reaction populated a previously unmeasured state at 1363 keV, which is most likely the single-particle 3p1/2 state expected above the N=82 shell closure. The data were analyzed using finite range adiabatic wave calculations and the results compared with the previous analysis using the distorted wave Born approximation. Angular distributions for the ground and first excited states are consistent with the previous tentative spin and parity assignments. Spectroscopic factors extracted from the differential cross sections are similar to those found for the one neutron states beyond the benchmark doubly-magic nucleus 208Pb.Comment: 22 pages, 7 figure

Recombination rate and selection strength in HIV intra-patient evolution

The evolutionary dynamics of HIV during the chronic phase of infection is driven by the host immune response and by selective pressures exerted through drug treatment. To understand and model the evolution of HIV quantitatively, the parameters governing genetic diversification and the strength of selection need to be known. While mutation rates can be measured in single replication cycles, the relevant effective recombination rate depends on the probability of coinfection of a cell with more than one virus and can only be inferred from population data. However, most population genetic estimators for recombination rates assume absence of selection and are hence of limited applicability to HIV, since positive and purifying selection are important in HIV evolution. Here, we estimate the rate of recombination and the distribution of selection coefficients from time-resolved sequence data tracking the evolution of HIV within single patients. By examining temporal changes in the genetic composition of the population, we estimate the effective recombination to be r=1.4e-5 recombinations per site and generation. Furthermore, we provide evidence that selection coefficients of at least 15% of the observed non-synonymous polymorphisms exceed 0.8% per generation. These results provide a basis for a more detailed understanding of the evolution of HIV. A particularly interesting case is evolution in response to drug treatment, where recombination can facilitate the rapid acquisition of multiple resistance mutations. With the methods developed here, more precise and more detailed studies will be possible, as soon as data with higher time resolution and greater sample sizes is available.Comment: to appear in PLoS Computational Biolog

Bis(phenyl­sulfin­yl)methane

Two independent mol­ecules comprise the asymmetric unit of the title compound, C13H12O2S2, which differ in terms of minor variations in the relative orientations of the benzene rings [the O–S–C–C torsion angles for the first independent mol­ecule are −6.66 (17) and −12.88 (19)° compared with −21.70 (18) and 4.83 (16)° for the second mol­ecule]. Supra­molecular chains sustained by C—H⋯O contacts and aligned along the a axis are found in the crystal structure. These are held in place in the three dimensional structure by C—H⋯π inter­actions