52,909 research outputs found
A tale of two cinnamons: A comparative review of the clinical evidence of Cinnamomum verum and C. cassia as diabetes interventions
Objective: This review investigates the effectiveness of two cinnamon species, Cinnamomum verum and C. cassia, in diabetes management; their impact on related health conditions and relevant parameters in healthy individuals and safety issues.
Methods: PubMed, Cochrane Library, and ScienceDirect were searched from 2000 up to April 2018 for clinical trials using either C. verum or C. cassia in controlling blood glucose and other diabetes-related parameters and conditions.
Results: A total of twenty-five studies (n=997) were included for reviewing clinical evidence. Among these trials, fifteen studies investigated the effects on type II diabetes mellitus (T2DM) patients (n=831), four investigated subjects with related clinical conditions (n=82), and six investigated healthy individuals (n=84). Nineteen studies used C. cassia and six used C. verum. Results suggested C. cassia helped manage diabetes at 3-6g, while the effectiveness of C. verum remained inconclusive. In addition, the chemical properties of C. cassia and C. verum differ considerably. Of note, C. cassia contains high levels of the potentially hepatotoxic constituent coumarin. A skin rash was the only adverse event reported.
Conclusion: While evidence supports the therapeutic benefit of C. cassia, interchangeability of C. cassia and C. verum remains inconclusive. Further research is warranted to address the effectiveness and safety of these cinnamon species. Given the potential hepatotoxicity of C. cassia, RCTs that include liver function tests are required. Robust RCTs on C. verum are recommended to establish if its efficacy can match its safety profile
Are sage, rosemary and lemon balm effective interventions in dementia? A narrative review of the clinical evidence
Introduction
Dementia is a common, progressive disorder impairing brain function and affecting sufferers and caregivers’ wellbeing. Numbers of dementia patients will increase as the population ages. Rosmarinic acid is a natural compound with choline esterase inhibitory potency found in members of the botanical family lamiaceae, including sage, rosemary, and lemon balm, suggesting potential efficacy in dementia intervention. This study aimed to evaluate effectiveness of these herbs based on a review of randomised controlled trials.
Methods
Database searches were conducted separately for each herb using PubMed, the Cochrane Library, and ScienceDirect for clinical evidence for sage (Salvia officinalis L. or S. lavandulaefolia Vahl), rosemary (Rosmarinus officinalis L.), and lemon balm (Melissa officinalis L.), administered individually.
Results
Database searching identified 235, 112, and 177 articles for sage, rosemary, and lemon balm, respectively. From these, eight for sage, five for rosemary and eight for lemon balm met inclusion criteria. Trials were analysed based on the study designs and summarized as narrative synthesis as data were heterogeneous in terms of the target populations, herbal preparations and administration methods.
Studies suggested sage spp. could improve cognitive performance and alertness. Rosemary could improve cognitive performance and alertness. Among eight articles identified on lemon balm, seven studies found it effective in improving mood or cognition. One study found no effect.
Conclusions
Some clinical evidence supports the benefit of these herbs in dementia intervention. However, methodological heterogeneity and variable trial quality made information synthesis difficult. Further research is required to determine dosage and intervention periods
Exploiting correlogram structure for robust speech recognition with multiple speech sources
This paper addresses the problem of separating and recognising speech in a monaural acoustic mixture with the presence of competing speech sources. The proposed system treats sound source separation and speech recognition as
tightly coupled processes. In the first stage sound source separation is performed in the correlogram domain. For periodic sounds, the correlogram exhibits symmetric tree-like structures whose stems are located on the delay
that corresponds to multiple pitch periods. These pitch-related structures are exploited in the study to group spectral components at each time frame. Local
pitch estimates are then computed for each spectral group and are used to form simultaneous pitch tracks for temporal integration. These processes segregate a spectral representation of the acoustic mixture into several time-frequency regions such that the energy in each region is likely to have originated from a single periodic sound source. The identified time-frequency regions, together
with the spectral representation, are employed by a `speech fragment decoder' which employs `missing data' techniques with clean speech models to simultaneously search for the acoustic evidence that best matches model sequences. The paper presents evaluations based on artificially mixed simultaneous speech utterances. A coherence-measuring experiment is first reported which quantifies the consistency of the identified fragments with a single source. The system is then evaluated in a speech recognition task and compared to a conventional fragment generation approach. Results show that the proposed system produces more coherent fragments over different conditions,
which results in significantly better recognition accuracy
The Spectral Evolution of Transient Anomalous X-ray Pulsar XTE J1810--197
(Abridged) We present a multi-epoch spectral study of the Transient Anomalous
X-ray Pulsar XTE J1810-197 obtained with the XMM X-ray telescope. Four
observations taken over the course of a year reveal strong spectral evolution
as the source fades from outburst. The origin of this is traced to the
individual decay rates of the pulsar's spectral components. A 2-T fit at each
epoch requires nearly constant temperatures of kT=0.25 & 0.67 keV while the
component luminosities decrease exponentially with tau=900 & 300d,
respectively. One possible interpretation is that the slowly decaying cooler
component is the radiation from a deep heating event that affected a large
fraction of the crust, while the hotter component is powered by external
surface heating at the foot-points of twisted magnetic field lines, by
magnetospheric currents that are decaying more rapidly. The energy-dependent
pulse profile of XTE J1810-197 is well modeled at all epochs by the sum of a
sine and triangle function. These profiles peak at the same phase, suggesting a
concentric surface emission geometry. The spectral and pulse evolution together
argue against the presence of a significant ``power-law'' contribution to the
X-ray spectrum below 8 keV. The extrapolated flux is projected to return to the
historic quiescent level, characterized by an even cooler blackbody spectrum,
by the year 2007.Comment: 12 pages, 6 Figures, Latex, emulateapj. To appear in the
Astrophysical Journa
Assessment of casting filling by modeling surface entrainment events using CFD
The reliability of cast components is dependent on the quality of the casting process. During this highly transient filling phase the prevention of free surface turbulence and consequential oxide entrainment is critical to ensure the mechanical integrity of the component. Past research has highlighted a number of events that lead to entrainment of surface oxides. Using FLOW-3D, flow structures that result in surface entrainment events have been simulated and an algorithm developed that allows entrainment and defect motion to be tracked. This enables prediction of the quantity and motion of oxide film generated from each event. The algorithm was tested experimentally and compared to experimental data from previously published work. A quantitative criterion is proposed to assess the damage of each type of event. Complete running systems have also been studied to understand how they could be assessed for quality of filling based on the flows within them
Millimeter wave experiment for ATS-F
A detailed description of spaceborne equipment is provided. The equipment consists of two transmitters radiating signals at 20 and 30 GHz from either U.S. coverage horn antennas or a narrow beam parabolic antenna. Three modes of operation are provided: a continuous wave mode, a multitone mode in which nine spectral lines having 180 MHz separation and spaced symmetrically about each carrier, and a communications mode in which communications signals from the main spacecraft transponder are modulated on the two carriers. Detailed performance attained in the flight/prototype model of the equipment is presented both under laboratory conditions and under environmental extremes. Provisions made for ensuring reliability in space operation are described. Also described the bench test equipment developed for use with the experiment, and a summary of the new technology is included
Supersymmetry Constraints on Type IIB Supergravity
Supersymmetry is used to derive conditions on higher derivative terms in the
effective action of type IIB supergravity. Using these conditions, we are able
to prove earlier conjectures that certain modular invariant interactions of
order alpha' **3 relative to the Einstein-Hilbert term are proportional to
eigenfunctions of the Laplace operator on the fundamental domain of SL(2,Z). We
also discuss how these arguments generalize to terms of higher order in alpha',
as well as to compactifications of supergravity.Comment: 31 pages, harvmac (b); minor correction
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