Synthesis and Application of An Organic Analytical Reagent

This work concerns the reaction of the primary amine, 2-amino- 2- methyl-1-propanol with carbon disulfide to produce the amine salt of 1-methyl-(1-methylol)-ethyldithiocarbamic acid. This salt is then investigated to determine its physical properties and the possibility of use in copper analysis. A report is given on the reaction, and the purification and analysis of the reaction product. The colored reaction of the amine salt with copper and other metal ions is listed, and an analytical procedure for the determination of trace amounts of copper is given. Using the procedure described, accurate determinations of copper concentration to one ppm were obtained. The effect of pH on fading of the colored copper thiocarbamate was investigated and found to be negligible between the range of pH from 4 to 8. An attempt was made to determine if the colored compound formed by reaction of the amine salt with copper was a chelate. Potentiometric and precipitation titrations were carried out with inconclusive results

Influence of a magnetic field on the viscosity of a dilute gas consisting of linear molecules.

The viscomagnetic effect for two linear molecules, N2 and CO2, has been calculated in the dilute-gas limit directly from the most accurate ab initio intermolecular potential energy surfaces presently available. The calculations were performed by means of the classical trajectory method in the temperature range from 70 K to 3000 K for N2 and 100 K to 2000 K for CO2, and agreement with the available experimental data is exceptionally good. Above room temperature, where no experimental data are available, the calculations provide the first quantitative information on the magnitude and the behavior of the viscomagnetic effect for these gases. In the presence of a magnetic field, the viscosities of nitrogen and carbon dioxide decrease by at most 0.3% and 0.7%, respectively. The results demonstrate that the viscomagnetic effect is dominated by the contribution of the jj¯ polarization at all temperatures, which shows that the alignment of the rotational axes of the molecules in the presence of a magnetic field is primarily responsible for the viscomagnetic effect

Concealed Carry of Firearms: Facts vs. Fiction

arrying a concealed handgun in public has the potential to enable would-be victims of violent crime to thwart attempted acts of violence, but also poses potential threats to public safety. Because of these potential threats, states have historically regulated the carrying of concealed firearms. These regulations have included requiring a permit to carry a concealed weapon and basing the issuance of these permits on whether applicants met training, safety, and even personal character requirements. Additionally, states have limited the places in which the permit holder could carry a concealed firearm

Facile crystallization of Escherichia coli ketol-acid reductoisomerase

Ketol-acid reductoisomerase (EC 1.1.1.86) catalyses the second reaction in the biosynthesis of branched-chain amino acids. The reaction involves an Mg2+-dependent alkyl migration followed by an NADPH-dependent reduction of the 2-keto group. Here, the crystallization of the Escherichia coli enzyme is reported. A form with a C-terminal hexahistidine tag could be crystallized under 18 different conditions in the absence of NADPH or Mg2+ and a further six crystallization conditions were identified with one or both ligands. With the hexahistidine tag on the N-terminus, 20 crystallization conditions were found, some of which required the presence of NADPH, NADP(+), Mg2+ or a combination of ligands. Finally, the selenomethionine-substituted enzyme with the N-terminal tag crystallized under 15 conditions. Thus, the enzyme is remarkably easy to crystallize. Most of the crystals diffract poorly but several data sets were collected at better than 3.2 Angstrom resolution; attempts to phase them are currently in progress

Technologies of birth and models of midwifery care

This article is based on a study of a reform in the organisation of maternity services in the United Kingdom, which aimed towards developing a more woman-centred model of care. After decades of fragmentation and depersonalisation of care, associated with the shift of birth to a hospital setting, pressure by midwives and mothers prompted government review and a relatively radical turnaround in policy. However, the emergent model of care has been profoundly influenced by concepts and technologies of monitoring. The use of such technologies as ultrasound scans, electronic foetal monitoring and oxytocic augmentation of labour, generally supported by epidural anaesthesia for pain relief, have accompanied the development of a particular ecological model of birth – often called active management –, which is oriented towards the idea of an obstetric norm. Drawing on analysis of women’s narrative accounts of labour and birth, this article discusses the impact on women’s embodiment in birth, and the sources of information they use about the status of their own bodies, their labour and that of the child. It also illustrates how the impact on women’s experiences of birth may be mediated by a relational model of support, through the provision of caseload midwifery care

Low temperature structural phase transition and incommensurate lattice modulation in the spin gap compound BaCuSi2O6

Results of high resolution x-ray diffraction experiments are presented for single crystals of the spin gap compound BaCuSi$_2$O$_6$ in the temperature range from 16 to 300 K. The data show clear evidence of a transition from the room temperature tetragonal phase into an incommensurately modulated orthorhombic structure below $\sim$100 K. This lattice modulation is characterized by a resolution limited wave vector {\bf q}$_{IC}$=(0,$\sim$0.13,0) and its 2$^{nd}$ and 3$^{rd}$ harmonics. The phase transition is first order and exhibits considerable hysteresis. This observation implies that the spin Hamiltonian representing the system is more complex than originally thought.Comment: 4 pages, 4 figure

Women's safety alerts in maternity care: is speaking up enough?

Patients’ contributions to safety include speaking up about their perceptions of being at risk. Previous studies have found that dismissive responses from staff discouraged patients from speaking up. A Care Quality Commission investigation of a maternity service where serious incidents occurred found evidence that women had routinely been ignored and left alone in labour. Women using antenatal services hesitated to raise concerns that they felt staff might consider irrelevant. The Birthplace in England programme, which investigated the quality and safety of different places of birth for ‘low-risk’ women, included a qualitative organisational case study in four NHS Trusts. The authors collected documentary, observational and interview data from March to December 2010 including interviews with 58 postnatal women. A framework approach was combined with inductive analysis using NVivo8 software. Speaking up, defined as insistent and vehement communication when faced with failure by staff to listen and respond, was an unexpected finding mentioned in half the women's interviews. Fourteen women reported raising alerts about safety issues they felt to be urgent. The presence of a partner or relative was a facilitating factor for speaking up. Several women described distress and harm that ensued from staff failing to listen. Women are speaking up, but this is not enough: organisation-focused efforts are required to improve staff response. Further research is needed in maternity services and in acute and general healthcare on the effectiveness of safety-promoting interventions, including real-time patient feedback, patient toolkits and patient-activated rapid response calls

Dynamical stability of a thermally stratified intracluster medium with anisotropic momentum and heat transport

In weakly-collisional plasmas such as the intracluster medium (ICM), heat and momentum transport become anisotropic with respect to the local magnetic field direction. Anisotropic heat conduction causes the slow magnetosonic wave to become buoyantly unstable to the magnetothermal instability (MTI) when the temperature increases in the direction of gravity and to the heat-flux--driven buoyancy instability (HBI) when the temperature decreases in the direction of gravity. The local changes in magnetic field strength that attend these instabilities cause pressure anisotropies that viscously damp motions parallel to the magnetic field. In this paper we employ a linear stability analysis to elucidate the effects of anisotropic viscosity (i.e. Braginskii pressure anisotropy) on the MTI and HBI. By stifling the convergence/divergence of magnetic field lines, pressure anisotropy significantly affects how the ICM interacts with the temperature gradient. Instabilities which depend upon the convergence/divergence of magnetic field lines to generate unstable buoyant motions (the HBI) are suppressed over much of the wavenumber space, whereas those which are otherwise impeded by field-line convergence/divergence (the MTI) are strengthened. As a result, the wavenumbers at which the HBI survives largely unsuppressed in the ICM have parallel components too small to rigorously be considered local. This is particularly true as the magnetic field becomes more and more orthogonal to the temperature gradient. In contrast, the fastest-growing MTI modes are unaffected by anisotropic viscosity. However, we find that anisotropic viscosity couples slow and Alfven waves in such a way as to buoyantly destabilise Alfvenic fluctuations when the temperature increases in the direction of gravity. Consequently, many wavenumbers previously considered MTI-stable or slow-growing are in fact maximally unstable. (abridged)Comment: 15 pages, 7 figures, accepted by MNRAS; typos fixed and minor corrections made; color figures available at http://www-thphys.physics.ox.ac.uk/people/kunz/Kunz11_colorfigs.pd

The HBI in a quasi-global model of the intracluster medium

In this paper we investigate how convective instabilities influence heat conduction in the intracluster medium (ICM) of cool-core galaxy clusters. The ICM is a high-beta, weakly collisional plasma in which the transport of momentum and heat is aligned with the magnetic field. The anisotropy of heat conduction, in particular, gives rise to instabilities that can access energy stored in a temperature gradient of either sign. We focus on the heat-flux buoyancy-driven instability (HBI), which feeds on the outwardly increasing temperature profile of cluster cool cores. Our aim is to elucidate how the global structure of a cluster impacts on the growth and morphology of the linear HBI modes when in the presence of Braginskii viscosity, and ultimately on the ability of the HBI to thermally insulate cores. We employ an idealised quasi-global model, the plane-parallel atmosphere, which captures the essential physics -- e.g. the global radial profile of the cluster -- while letting the problem remain analytically tractable. Our main result is that the dominant HBI modes are localised to the the innermost (~<20%) regions of cool cores. It is then probable that, in the nonlinear regime, appreciable field-line insulation will be similarly localised. Thus, while radio-mode feedback appears necessary in the central few tens of kpc, heat conduction may be capable of offsetting radiative losses throughout most of a cool core over a significant fraction of the Hubble time. Finally, our linear solutions provide a convenient numerical test for the nonlinear codes that tackle the saturation of such convective instabilities in the presence of anisotropic transport.Comment: MNRAS, in press; minor modifications from v

Elucidating the specificity of binding of sulfonylurea herbicides to acetohydroxyacid synthase

ABSTRACT: Acetohydroxyacid synthase (AHAS, EC 2.2.1.6) is the target for the sulfonylurea herbicides, which act as potent inhibitors of the enzyme. Chlorsulfuron (marketed as Glean) and sulfometuron methyl (marketed as Oust) are two commercially important members of this family of herbicides. Here we report crystal structures of yeast AHAS in complex with chlorsulfuron (at a resolution of 2.19 Å), sulfometuron methyl (2.34 Å), and two other sulfonylureas, metsulfuron methyl (2.29 Å) and tribenuron methyl (2.58 Å). The structures observed suggest why these inhibitors have different potencies and provide clues about the differential effects of mutations in the active site tunnel on various inhibitors. In all of the structures, the thiamin diphosphate cofactor is fragmented, possibly as the result of inhibitor binding. In addition to thiamin diphosphate, AHAS requires FAD for activity. Recently, it has been reported that reduction of FAD can occur as a minor side reaction due to reaction with the carbanion/enamine of the hydroxyethylThDP intermediate that is formed midway through the catalytic cycle. Here we report that the isoalloxazine ring has a bent conformation that would account for its ability to accept electrons from the hydroxyethyl intermediate. Most sequence and mutation data suggest that yeast AHAS is a high-quality model for the plant enzyme