9,272 research outputs found

    Alcohol Induced Psychotic Disorder: a comparitive study in patients with alcohol dependance, schizophrenia and normal controls

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    Thesis(DMed (Psychiatry))-- University of Stellenbosch, 2007.Alcohol-induced psychotic disorder (also known as alcohol hallucinosis) is a complication of alcohol abuse that requires clinical differentiation from alcohol withdrawal delirium and schizophrenia. Although extensively described, few studies utilized standardized research instruments and brain-imaging has thus far been limited to case reports. The aim of this study was to prospectively compare four population groups (ie. patients with alcohol-induced psychotic disorder, schizophrenia, uncomplicated alcohol dependence and a healthy volunteer group) according to demographic, psychopathological and brainimaging variables utilizing (i) rating scales and (ii) single photon emission computed tomography (SPECT). The third component of the study was designed to investigate the (iii) effect of anti-psychotic treatment on the psychopathology and regional cerebral blood flow (rCBF) before and after six weeks of treatment with haloperidol. Effort was made to ensure exclusion of comorbid medical disorders, including substance abuse. The study provides further supportive evidence that alcohol-induced psychotic disorder can be distinguished from schizophrenia. Statistically significant differences in rCBF were demonstrated between the alcohol-induced psychotic disorder and other groups. Changes in frontal, temporal, parietal, occipital, thalamic and cerebellar rCBF showed statistically significant negative correlations with post-treatment improvement on psychopathological variables and imply dysfunction of these areas in alcohol-induced psychotic disorder. The study was unable to distinguish between pharmacological effects and improvement acccomplished by abstinence from alcohol.Stellenbosch: Stellenbosch Universit

    Accurate measurement of ^{13}C - ^{15}N distances with solid-state NMR

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    Solid-state NMR technique for measureing distances between hetero-nuclei in static powder samples is described. It is based on a two-dimensional single-echo scheme enhanced with adiabatic cross-polarization. As an example, the results for intra-molecular distances in α\alpha-crystalline form of glycine are presented. The measured NMR distances ^13 C(2) - ^15 N and ^13 C(1) - ^15 N are 1.496 ±\pm 0.002 \AA and 2.50 ±\pm 0.02 \AA, respectively.Comment: 12 page

    Fidelity enhancement by logical qubit encoding

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    We demonstrate coherent control of two logical qubits encoded in a decoherence free subspace (DFS) of four dipolar-coupled protons in an NMR quantum information processor. A pseudo-pure fiducial state is created in the DFS, and a unitary logical qubit entangling operator evolves the system to a logical Bell state. The four-spin molecule is partially aligned by a liquid crystal solvent, which introduces strong dipolar couplings among the spins. Although the system Hamiltonian is never fully specified, we demonstrate high fidelity control over the logical degrees of freedom. In fact, the DFS encoding leads to higher fidelity control than is available in the full four-spin Hilbert space.Comment: 10 pages, 2 figure

    Self-induced water intoxication : a case report

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    CITATION: Emsley, R. A. & Taljaard, J. J. F. 1988. Self-induced water intoxication : a case report. South African Medical Journal, 74:80-81.The original publication is available at http://www.samj.org.zaA 19-year-old female schizophrenic with self-induced water intoxication is described. Factors of pathogenic significance included primary polydipsia and non-maximal urinary diluting capacity.Publisher’s versio

    Thermodynamic aspects of materials' hardness: prediction of novel superhard high-pressure phases

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    In the present work we have proposed the method that allows one to easily estimate hardness and bulk modulus of known or hypothetical solid phases from the data on Gibbs energy of atomization of the elements and corresponding covalent radii. It has been shown that hardness and bulk moduli of compounds strongly correlate with their thermodynamic and structural properties. The proposed method may be used for a large number of compounds with various types of chemical bonding and structures; moreover, the temperature dependence of hardness may be calculated, that has been performed for diamond and cubic boron nitride. The correctness of this approach has been shown for the recently synthesized superhard diamond-like BC5. It has been predicted that the hypothetical forms of B2O3, diamond-like boron, BCx and COx, which could be synthesized at high pressures and temperatures, should have extreme hardness

    Periprocedural antithrombotic management for lumbar puncture: Association of British Neurologists clinical guideline

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    Lumbar puncture (LP) is an important and frequently performed invasive procedure for the diagnosis and management of neurological conditions. There is little in the neurological literature on the topic of periprocedural management of antithrombotics in patients undergoing LP. Current practice is therefore largely extrapolated from guidelines produced by anaesthetic bodies on neuraxial anaesthesia, haematology groups advising on periprocedural management of antiplatelet agents and anticoagulants, and by neuroradiology on imaging-guided spinal procedures. This paper summarises the existing literature on the topic and offers recommendations to guide periprocedural antithrombotic management for LP, based on the consolidation of the best available evidence. ​. [Abstract copyright: © Author(s) (or their employer(s)) 2018. No commercial re-use. See rights and permissions. Published by BMJ.

    Quantum information processing using strongly-dipolar coupled nuclear spins

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    Dipolar coupled homonuclear spins present challenging, yet useful systems for quantum information processing. In such systems, eigenbasis of the system Hamiltonian is the appropriate computational basis and coherent control can be achieved by specially designed strongly modulating pulses. In this letter we describe the first experimental implementation of the quantum algorithm for numerical gradient estimation on the eigenbasis of a four spin system.Comment: 5 pages, 5 figures, Accepted in PR

    First principles investigations of the electronic, magnetic and chemical bonding properties of CeTSn (T=Rh,Ru)

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    The electronic structures of CeRhSn and CeRuSn are self-consistently calculated within density functional theory using the local spin density approximation for exchange and correlation. In agreement with experimental findings, the analyses of the electronic structures and of the chemical bonding properties point to the absence of magnetization within the mixed valent Rh based system while a finite magnetic moment is observed for trivalent cerium within the Ru-based stannide, which contains both trivalent and intermediate valent Ce.Comment: 6 pages, 7 figures, for more information see http://www.physik.uni-augsburg.de/~eyert

    Design of Strongly Modulating Pulses to Implement Precise Effective Hamiltonians for Quantum Information Processing

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    We describe a method for improving coherent control through the use of detailed knowledge of the system's Hamiltonian. Precise unitary transformations were obtained by strongly modulating the system's dynamics to average out unwanted evolution. With the aid of numerical search methods, pulsed irradiation schemes are obtained that perform accurate, arbitrary, selective gates on multi-qubit systems. Compared to low power selective pulses, which cannot average out all unwanted evolution, these pulses are substantially shorter in time, thereby reducing the effects of relaxation. Liquid-state NMR techniques on homonuclear spin systems are used to demonstrate the accuracy of these gates both in simulation and experiment. Simulations of the coherent evolution of a 3-qubit system show that the control sequences faithfully implement the unitary operations, typically yielding gate fidelities on the order of 0.999 and, for some sequences, up to 0.9997. The experimentally determined density matrices resulting from the application of different control sequences on a 3-spin system have overlaps of up to 0.99 with the expected states, confirming the quality of the experimental implementation.Comment: RevTeX3, 11 pages including 2 tables and 5 figures; Journal of Chemical Physics, in pres

    Structural insights into the autoregulation and cooperativity of the human transcription factor Ets-2

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    Ets-2, like its closely related homologue Ets-1, is a member of the Ets family of DNA binding transcription factors. Both proteins are subject to multiple levels of regulation of their DNA binding and transactivation properties. One such regulatory mechanism is the presence of an autoinhibitory module, which in Ets-1 allosterically inhibits the DNA binding activity. This inhibition can be relieved by interaction with protein partners or cooperative binding to closely separated Ets binding sites in a palindromic arrangement. In this study we describe the 2.5 Å resolution crystal structure of a DNA complex of the Ets-2 Ets domain. The Ets domain crystallized with two distinct species in the asymmetric unit, which closely resemble the autoinhibited and DNA bound forms of Ets-1. This discovery prompted us to re-evaluate the current model for the autoinhibitory mechanism and the structural basis for cooperative DNA binding. In contrast to Ets-1, in which the autoinhibition is caused by a combination of allosteric and steric mechanisms, we were unable to find clear evidence for the allosteric mechanism in Ets-2. We also demonstrated two possibly distinct types of cooperative binding to substrates with Ets binding motifs separated by four and six base pairs and suggest possible molecular mechanisms for this behavior
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