9,272 research outputs found
Alcohol Induced Psychotic Disorder: a comparitive study in patients with alcohol dependance, schizophrenia and normal controls
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
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 -crystalline form of
glycine are presented. The measured NMR distances ^13 C(2) - ^15 N and ^13 C(1)
- ^15 N are 1.496 0.002 \AA and 2.50 0.02 \AA, respectively.Comment: 12 page
Fidelity enhancement by logical qubit encoding
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
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
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
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
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)
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
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
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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