Self-reported use of novel psychoactive substances in a US nationally representative survey: Prevalence, correlates, and a call for new survey methods to prevent underreporting

Background: In recent years, there has been an increase in emergence and use of novel psychoactive substances (NPS) in the US and worldwide. However, there is little published epidemiological survey data estimating the prevalence of use in the US. Method: Data on self-reported NPS use came from the National Survey of Drug Use and Health (2009–2013), a national representative sample of non-institutionalized individuals in the US. Subjects were asked to provide names of (non-traditional) drugs they used that they were not specifically asked about. We examined lifetime prevalence and sociodemographic correlates of self-reported use of new and uncommon synthetic drugs (NPS) among subjects ages 12–34-years-old. Results: 1.2% of subjects self-reported any use of the 57 NPS we examined. Use of psychedelic tryptamines (primarily DMT) was most common, followed by psychedelic phenethylamines (e.g., 2C series) and synthetic cannabinoids. Prevalence of self-reported use of NPS increased from 2009 to 2013 and use was most common among males, whites, older subjects, those of lower income, and among those residing in cities. Lifetime use of various other illicit drugs (e.g., LSD, cocaine, ecstasy/MDMA) was highly prevalent among NPS users. Conclusion: This the first study reporting on use of a variety of NPS in a nationally representative US sample; however, use appears to be underreported as other national data suggest higher rates of NPS (e.g., synthetic cannabinoid) use. Developing more adaptable survey tools and systematically assessing NPS use would allow researchers to ask about hundreds of NPS and improve reporting as new drugs continue to rapidly emerge

DNA bending by M.EcoKI methyltransferase is coupled to nucleotide flipping

The maintenance methyltransferase M.EcoKI recognizes the bipartite DNA sequence 5′-AACNNNNNNGTGC-3′, where N is any nucleotide. M.EcoKI preferentially methylates a sequence already containing a methylated adenine at or complementary to the underlined bases in the sequence. We find that the introduction of a single-stranded gap in the middle of the non-specific spacer, of up to 4 nt in length, does not reduce the binding affinity of M.EcoKI despite the removal of non-sequence-specific contacts between the protein and the DNA phosphate backbone. Surprisingly, binding affinity is enhanced in a manner predicted by simple polymer models of DNA flexibility. However, the activity of the enzyme declines to zero once the single-stranded region reaches 4 nt in length. This indicates that the recognition of methylation of the DNA is communicated between the two methylation targets not only through the protein structure but also through the DNA structure. Furthermore, methylation recognition requires base flipping in which the bases targeted for methylation are swung out of the DNA helix into the enzyme. By using 2-aminopurine fluorescence as the base flipping probe we find that, although flipping occurs for the intact duplex, no flipping is observed upon introduction of a gap. Our data and polymer model indicate that M.EcoKI bends the non-specific spacer and that the energy stored in a double-stranded bend is utilized to force or flip out the bases. This energy is not stored in gapped duplexes. In this way, M.EcoKI can determine the methylation status of two adenine bases separated by a considerable distance in double-stranded DNA and select the required enzymatic response

Random coil dimensions of poly(diethyl siloxane)

A sample of high molecular weight poly(diethyl siloxane), [Si(C2H5)2---O---]x, (PDES) was separated into a series of fractions by means of liquid-liquid precipitations. Four of the fractions were studied by osmometry and viscometry in toluene at 25[deg]C. The resulting values of the number-average molecular weight, second virial coefficient, and intrinsic viscosity indicate that the unperturbed dimensions of PDES are essentially the same as those of poly(dimethyl siloxane) (PDMS) of the same chain length. Thus, differences in intramolecular interactions between these two chains have little effect on their unperturbed dimensions. Most pertinent in this regard are interactions between the side chains, which are favourable in trans conformations in both PDES and PDMS. These favourable interactions in trans conformations would be enhanced in the case of the ethyl groups in PDES, but this effect is apparently offset by a comparable increase in favourable interactions between ethyl groups and oxygen atoms in the competing gauche conformations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22625/1/0000175.pd

Magnetic Lattice Dynamics of the Oxygen-Free FeAs Pnictides: How Sensitive are Phonons to Magnetic Ordering?

To shed light on the role of magnetism on the superconducting mechanism of the oxygen-free FeAs pnictides, we investigate the effect of magnetic ordering on phonon dynamics in the low-temperature orthorhombic parent compounds, which present a spin-density wave. The study covers both the 122 (AFe2As2; A=Ca, Sr, Ba) and 1111 (AFeAsF; A=Ca, Sr) phases. We extend our recent work on the Ca (122 and 1111) and Ba (122) cases by treating computationally and experimentally the 122 and 1111 Sr compounds. The effect of magnetic ordering is investigated through detailed non-magnetic and magnetic lattice dynamical calculations. The comparison of the experimental and calculated phonon spectra shows that the magnetic interactions/ordering have to be included in order to reproduce well the measured density of states. This highlights a spin-correlated phonon behavior which is more pronounced than the apparently weak electron-phonon coupling estimated in these materials. Furthermore, there is no noticeable difference between phonon spectra of the 122 Ba and Sr, whereas there are substantial differences when comparing these to CaFe2As2 originating from different aspects of structure and bonding

HST and Spitzer Observations of the HD 207129 Debris Ring

A debris ring around the star HD 207129 (G0V; d = 16.0 pc) has been imaged in scattered visible light with the ACS coronagraph on the Hubble Space Telescope and in thermal emission using MIPS on the Spitzer Space Telescope at 70 microns (resolved) and 160 microns (unresolved). Spitzer IRS (7-35 microns) and MIPS (55-90 microns) spectrographs measured disk emission at >28 microns. In the HST image the disk appears as a ~30 AU wide ring with a mean radius of ~163 AU and is inclined by 60 degrees from pole-on. At 70 microns it appears partially resolved and is elongated in the same direction and with nearly the same size as seen with HST in scattered light. At 0.6 microns the ring shows no significant brightness asymmetry, implying little or no forward scattering by its constituent dust. With a mean surface brightness of V=23.7 mag per square arcsec, it is the faintest disk imaged to date in scattered light.Comment: 28 pages, 8 figure

Neonatal hyperoxia promotes asthma-like features through IL-33–dependent ILC2 responses

Background Premature infants often require oxygen supplementation and, therefore, are exposed to oxidative stress. Following oxygen exposure, preterm infants frequently develop chronic lung disease and have a significantly increased risk of asthma. Objective We sought to identify the underlying mechanisms by which neonatal hyperoxia promotes asthma development. Methods Mice were exposed to neonatal hyperoxia followed by a period of room air recovery. A group of mice was also intranasally exposed to house dust mite antigen. Assessments were performed at various time points for evaluation of airway hyperresponsiveness, eosinophilia, mucus production, inflammatory gene expression, and TH and group 2 innate lymphoid cell (ILC2) responses. Sera from term- and preterm-born infants were also collected and levels of IL-33 and type 2 cytokines were measured. Results Neonatal hyperoxia induced asthma-like features including airway hyperresponsiveness, mucus hyperplasia, airway eosinophilia, and type 2 pulmonary inflammation. In addition, neonatal hyperoxia promoted allergic TH responses to house dust mite exposure. Elevated IL-33 levels and ILC2 responses were observed in the lungs most likely due to oxidative stress caused by neonatal hyperoxia. IL-33 receptor signaling and ILC2s were vital for the induction of asthma-like features following neonatal hyperoxia. Serum IL-33 levels correlated significantly with serum levels of IL-5 and IL-13 but not IL-4 in preterm infants. Conclusions These data demonstrate that an axis involving IL-33 and ILC2s is important for the development of asthma-like features following neonatal hyperoxia and suggest therapeutic potential for targeting IL-33, ILC2s, and oxidative stress to prevent and/or treat asthma development related to prematurity

Laser-Induced Changes in Intraretinal Oxygen Distribution in Pigmented Rabbits

PURPOSE. To make the first measurements of intraretinal oxygen distribution and consumption after laser photocoagulation of the retina and to compare the efficiency of micropulsed (MP) and continuous wave (CW) laser delivery in achieving an oxygen benefit in the treated area. METHODS. Oxygen-sensitive microelectrodes were used to measure oxygen tension as a function of retinal depth before and after laser treatment in anesthetized, mechanically ventilated, Dutch Belted rabbits (n ϭ 11). Laser lesions were created by using a range of power levels from an 810-nm diode laser coupled with an operating microscope delivery system. MP duty cycles of 5%, 10%, and 15% were compared with CW delivery in each eye. RESULTS. Sufficient power levels of both the CW and MP laser reduced outer retinal oxygen consumption and increased oxygen level within the retina. At these power levels, which correlated with funduscopically visible lesions, there was histologically visible damage to the RPE and photoreceptors. Retinal damage was energy dependent but short-duty-cycle MP delivery was more selective in terms of retinal cell damage, with a wider safety range in comparison with CW delivery. CONCLUSIONS. The relationship between laser power level and mode of delivery and the resultant changes in oxygen metabolism and oxygen level in the retina was determined. Only partial destruction of RPE and photoreceptors is necessary, to produce a measurable oxygen benefit in the treated area of retina. (Invest Ophthalmol Vis Sci. 2005;46:988 -999

V445 Puppis: Dustier than a Thousand Novae

V445 Puppis, the only known Galactic helium nova, is a unique test bed to verify supernova (SN) theories in the single-degenerate channel that involve a white dwarf (WD) accreting matter from a helium-rich donor. An estimate of the mass of the helium shell on the WD is crucial to deciding whether or not it will undergo an SN detonation. In this context, this study estimates the dust and ejecta masses in the 2000 November eruption of V445 Pup. Subsequent to its outburst, the star became cocooned in a dust envelope. An analysis of the spectral energy distribution (SED) of the dust using infrared data shows that V445 Pup produced at least 10−3 M ⊙ of dust, which is unprecedented for a classical or recurrent nova. The SED can be explained by a combination of a cold dust component at 105 ± 10 K, mass (1.9 ± 0.8) × 10−3 M ⊙, and a warm dust component at 255 ± 10 K, mass (2.2 ± 1.2) × 10−5 M ⊙. For a conservative choice of the gas-to-dust mass ratio in the range 10–100, the mass of the ejecta is 0.01–0.1 M ⊙. Such a high mass range raises the question: why did V445 Pup not detonate as a Type Ia SN as is predicted in certain double-detonation sub-Chandrasekhar supernovae formalisms? We reexamine the nature of V445 Pup and discuss its role as a potential SN progenitor