The magnetic environment of the Orion-Eridanus superbubble as revealed by Planck

Using the 353-GHz polarization observations by the Planck satellite we characterize the magnetic field in the Orion-Eridanus superbubble, a nearby expanding structure that spans more than 1600 square degrees in the sky. We identify a region of both low dispersion of polarization orientations and high polarization fraction associated with the outer wall of the superbubble identified in the most recent models of the large-scale shape of the region. We use the Davis-Chandrasekhar-Fermi method to derive plane-of-the-sky magnetic field strengths of tens of microGauss toward the southern edge of the bubble. The comparison of these values with existing Zeeman splitting observations of HI in emission suggests that the large-scale magnetic field in the region was primarily shaped by the expanding superbubble.Comment: 7 pages, 8 figures. Accepted for publication as a Letter in A&A, section 1. Letters to the Editor (08/12/2017

Mid-J CO observations of Perseus B1-East 5: evidence for turbulent dissipation via low-velocity shocks

Giant molecular clouds contain supersonic turbulence and magnetohydrodynamic simulations predict that this turbulence should decay rapidly. Such turbulent dissipation has the potential to create a warm (T ~100 K) gas component within a molecular cloud. We present observations of the CO J = 5-4 and 6-5 transitions, taken with the Herschel Space Observatory, towards the Perseus B1-East 5 region. We combine these new observations with archival measurements of lower rotational transitions and fit photodissociation region models to the data. We show that Perseus B1-E5 has an anomalously large CO J = 6-5 integrated intensity, consistent with a warm gas component existing within the region. This excess emission is consistent with predictions for shock heating due to the dissipation of turbulence in low velocity shocks with the shocks having a volume filling factor of 0.15 per cent. We find that B1-E has a turbulent energy dissipation rate of 3.5 x 10$^{32}$ erg / s and a dissipation time-scale that is only a factor of 3 larger than the flow crossing time-scale.Comment: 18 pages, 15 figures, 4 tables, accepted by MNRAS, fixed errors described in erratu

Validated method for the detection and quantitation of synthetic cannabinoids in whole blood and urine, and its application to postmortem cases in Johannesburg, South Africa

A LC-HRMS (liquid chromatography coupled with high resolution mass  spectrometry) method for the detection and quantitation of several synthetic cannabinoids (JWH-018, JWH-019, JWH-073, JWH-081, JWH-122 JWH-200, JWH-250, AM-2201, (±)-CP 47,497, (C8)-CP 47,497, HU-211) and selected metabolites (JWH-018 N-(4-hydroxypentyl) and JWH-073 N-(3-hydroxybutyl)) in whole blood and urine was developed and validated. These methods were applied to postmortem cases from the Johannesburg Forensic Pathology Services Medicolegal Laboratory (FPS-MLL) to assess the prevalence of these synthetic cannabinoids amongst the local postmortem population. Urine samples were extracted utilizing a solid phase extraction (SPE) method, while blood samples were extracted utilizing liquid-liquid extraction (LLE) method. The accuracy of the analytes ranged from 88–107 % in whole blood (relative standard deviation (RSD) = 7.5–15.0 %), and from 95–109 % in urine (RSD = 4.9–11.9 %). The limits of detection (LOD) and the limits of quantitation (LOQ) for the analytes ranged between 0.675 ngmL–1 and 3.375 ngmL–1 in whole blood, and between 0.225 ngmL–1 to 3.375 ngmL–1 in urine. None of the postmortem cases tested positive for any of the targeted analytes. The sample population could be extended to living subjects such as those in drug rehabilitation centres or in hospitals to obtain a more accurate representation of the overall usage in South Africa.Keywords: Toxicology, LC-HRMS, synthetic cannabinoids, whole blood, urin

Solid‐Phase Supports for Oligonucleotide Synthesis

This unit begins with a discussion of the advantages and disadvantages of oligonucleotide synthesis using solid supports. The physical and chemical properties of solid‐phase supports are discussed in terms of their suitability for oligonucleotide synthesis. In addition, the unit outlines the properties of linkers used for transient or permanent attachment of properly protected nucleosides to the derivatized support, as well as strategies for coupling nucleosides to linkers and conditions for the release of synthetic oligonucleotides from specific supports.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143613/1/cpnc0301.pd

Kinematics of dense gas in the L1495 filament

We study the kinematics of the dense gas of starless and protostellar cores traced by the N2D+(2-1), N2H+(1-0), DCO+(2-1), and H13CO+(1-0) transitions along the L1495 filament and the kinematic links between the cores and the surrounding molecular cloud. We measure velocity dispersions, local and total velocity gradients and estimate the specific angular momenta of 13 dense cores in the four transitions using the on-the-fly observations with the IRAM 30 m antenna. To study a possible connection to the filament gas, we use the fit results of the C18O(1-0) survey performed by Hacar et al. (2013). All cores show similar properties along the 10 pc-long filament. N2D+(2-1) shows the most centrally concentrated structure, followed by N2H+(1-0) and DCO+(2-1), which show similar spatial extent, and H13CO+(1-0). The non-thermal contribution to the velocity dispersion increases from higher to lower density tracers. The change of magnitude and direction of the total velocity gradients depending on the tracer used indicates that internal motions change at different depths within the cloud. N2D+ and N2H+ show smaller gradients than the lower density tracers DCO+ and H13CO+, implying a loss of specific angular momentum at small scales. At the level of cloud-core transition, the core's external envelope traced by DCO+ and H13CO+ is spinning up, consistent with conservation of angular momentum during core contraction. C18O traces the more extended cloud material whose kinematics is not affected by the presence of dense cores. The decrease in specific angular momentum towards the centres of the cores shows the importance of local magnetic fields to the small scale dynamics of the cores. The random distributions of angles between the total velocity gradient and large scale magnetic field suggests that the magnetic fields may become important only in the high density gas within dense cores.Comment: Accepted for publication in A&A. The abstract is shortene

Mid-J CO Shock Tracing Observations of Infrared Dark Clouds I

Infrared dark clouds (IRDCs) are dense, molecular structures in the interstellar medium that can harbour sites of high-mass star formation. IRDCs contain supersonic turbulence, which is expected to generate shocks that locally heat pockets of gas within the clouds. We present observations of the CO J = 8-7, 9-8, and 10-9 transitions, taken with the Herschel Space Observatory, towards four dense, starless clumps within IRDCs (C1 in G028.37+00.07, F1 and F2 in G034.43+0007, and G2 in G034.77-0.55). We detect the CO J = 8-7 and 9-8 transitions towards three of the clumps (C1, F1, and F2) at intensity levels greater than expected from photodissociation region (PDR) models. The average ratio of the 8-7 to 9-8 lines is also found to be between 1.6 and 2.6 in the three clumps with detections, significantly smaller than expected from PDR models. These low line ratios and large line intensities strongly suggest that the C1, F1, and F2 clumps contain a hot gas component not accounted for by standard PDR models. Such a hot gas component could be generated by turbulence dissipating in low velocity shocks.Comment: 14 pages, 8 figures, 5 tables, accepted by A&A, minor updates to match the final published versio

Textural and rheological properties of stevia ice cream

Ice cream contains high sugar content and therefore it is in contradiction with the concept of healthy diet. The objective of this study is to determine the suitability of using stevia as an alternative natural sweetener in making ice cream. In-house ice cream formulation (as the control) and three different concentrations of stevia ice cream formulations of (A, B and C) were used. Physical properties of the ice cream such as the overrun, total soluble solid, meltdown rate, rheology, and textural properties were evaluated. All ice cream samples exhibited a non-Newtonian flow with pseudoplastic behavior. Stevia ice cream has a lower melting rate and has a higher sustainability. The power law also showed that apparent viscosities of stevia ice cream were higher. Therefore, stevia can be used as a natural sugar substitute in ice cream production