1,292 research outputs found
A simple automated system for the routine production of 99mTc by methyl-ethyl-ketone extraction
A relatively simple, automated system for the rapid, efficient and safe routine production of 99mTcM from 99Mo03 by the methyl-ethyl-ketone (MEK) extraction technique is described. The 4 phases of the extraction process - bubbling of air, phase separation, drawing off of 99mTc in MEK, and evaporation to dryness, are controlled by an automatic timer, suction-pressure pump and solenoid switches. The eluate was found to contain neither bacterial organisms or pyrogens nor significant levels of alumina and radio-isotopic impurities. With this system it is possible to make use of locally produced 99Mo, even of low specific activity for the routine production of 99mlc in any concentration required.S. Afr. Med. J., 48, 998 (1974)
Can a supernova be located by its neutrinos?
A future core-collapse supernova in our Galaxy will be detected by several
neutrino detectors around the world. The neutrinos escape from the supernova
core over several seconds from the time of collapse, unlike the electromagnetic
radiation, emitted from the envelope, which is delayed by a time of order
hours. In addition, the electromagnetic radiation can be obscured by dust in
the intervening interstellar space. The question therefore arises whether a
supernova can be located by its neutrinos alone. The early warning of a
supernova and its location might allow greatly improved astronomical
observations. The theme of the present work is a careful and realistic
assessment of this question, taking into account the statistical significance
of the various neutrino signals. Not surprisingly, neutrino-electron forward
scattering leads to a good determination of the supernova direction, even in
the presence of the large and nearly isotropic background from other reactions.
Even with the most pessimistic background assumptions, SuperKamiokande (SK) and
the Sudbury Neutrino Observatory (SNO) can restrict the supernova direction to
be within circles of radius and , respectively. Other
reactions with more events but weaker angular dependence are much less useful
for locating the supernova. Finally, there is the oft-discussed possibility of
triangulation, i.e., determination of the supernova direction based on an
arrival time delay between different detectors. Given the expected statistics
we show that, contrary to previous estimates, this technique does not allow a
good determination of the supernova direction.Comment: 11 pages including 2 figures. Revised version corrects typos, adds
some brief comment
Characterising Deadlines in Temporal Modal Defeasible Logic
We provide a conceptual analysis of several kinds of deadlines, represented in Temporal Modal Defeasible Logic. The paper presents a typology of deadlines, based on the following parameters: deontic operator, maintenance or achievement, presence or absence of sanctions, and persistence after the deadline. The deadline types are illustrated by a set of examples
Measurements of the LHC longitudinal resistive impedance with beam
The resistive part of the longitudinal impedance contributes to the heat deposition on different elements in the LHC ring including the beam screens, where it has to be absorbed by the cryogenic system and can be a practical limitation for the maximum beam intensity. In this paper, we present the first measurements of the LHC longitudinal resistive impedance with beam, done through synchronous phase shift measurements duringMachine Development sessions in 2012. Synchronous phase shift is measured for different bunch intensities and lengths using the high-precision LHC Beam Phase Module and then data are post-processed to further increase the accuracy. The dependence of the energy loss per particle on bunch length is then obtained and compared with the expected values found using the LHC impedance model
Carcinomatous Meningitis from Unknown Primary Carcinoma
Carcinomatous meningitis (CM) occurs in 3 to 8% of cancer patients. Patients present with a focal symptom, and multifocal signs are often found following neurological examination. The gold standard for diagnosis remains the demonstration of carcinomatous cells in the cerebrospinal fluid on cytopathological examination. Despite the poor prognosis, palliative treatment could improve quality of life and, in some cases, overall survival. We report on a patient who presented with vertigo, tinnitus and left-sided hearing loss followed by progressive diffuse facial nerve paralysis. Lumbar cerebrospinal fluid confirmed the diagnosis of CM. However, no primary tumor was discovered, even after multiple invasive investigations. This is the first reported case in the English-language medical literature of CM resulting from a carcinoma of unknown primary origin
Identification of antidiabetic compounds from the aqueous extract of Sclerocarya birrea leaves
SUPPLEMENTARY MATERIALS : TABLE S1: 1H NMR and 13C NMR data of Myricetin (1) in methanol-d4 compared to those reported [35] in DMSO-d6; TABLE S2: 1H NMR and 13C NMR data of Myricetin-3-O-β-D-glucuronide (2) in methanol-d4 compared to those reported [36] in methanol-d4; TABLE S3: 1H NMR and 13C NMR data of Quercetin-3-O-β-D-glucuronide (3) in methanol-d4 compared to those reported by [37] in methanol-d4; FIGURE S4: Relative Glucose uptake activity of Marula fractions in C2C12 myocytes over a range of 0.01-100µg/ml. Activity is expressed relative % to the baseline glucose uptake (control) set at 0% and the positive control insulin (Ins) set at 100%. Active fraction (fraction 3) exhibited comparable potency to Insulin. p value < * p < 0.05, ** p < 0.01. *** p < 0.001; FIGURE S5: ESI negative-mode BPI chromatogram of compound 1 (Myricetin) isolated from Fraction 4; FIGURE S6: ESI negative-mode BPI chromatogram of compound 2 (Myricetin3-O-β-D-glucuronide) isolated from Fraction 3; FIGURE S7: ESI negative-mode BPI chromatogram of compound 3 (Quercetin-3-O-β-D-glucuronide) isolated from Fraction 3; FIGURE S8: MS fragmentation pattern of peak 1 overlaid with MSMS fragmentation pattern of peak 1; FIGURE S9: MS fragmentation pattern of peak 2 overlaid with MSMS fragmentation pattern of peak 2; FIGURE S10: MS fragmentation pattern of peak 3 overlaid with MSMS fragmentation pattern of peak 3; FIGURE S11: MS fragmentation pattern of peak 4 overlaid with MSMS fragmentation pattern of peak 4; FIGURE S12: MS fragmentation pattern of peak 5 overlaid with MSMS fragmentation pattern of peak 5; FIGURE S13: MS fragmentation pattern of peak 6 overlaid with MSMS fragmentation pattern of peak 6.DATA AVAILABILITY STATEMENT : All the data supporting the findings of this study are available within the article and/or its Supplementary Materials.Diabetes, a prevalent metabolic condition with a wide range of complications, is fast becoming
a global health crisis. Herbal medicine and enhanced extracts are some of the therapeutic
options used in the management of diabetes mellitus. The plant-derived molecules and their suitable
structure modification have given many leads or drugs to the world such as metformin used as an
antidiabetic drug. The stem extract of Sclerocarya birrea has been reported as a potent antidiabetic
(glucose uptake) agent. However, the bioactive compounds have not been reported from S. birrea for
treatment of diabetes. In this study, the spray-dried aqueous leaf extracts of S. birrea were investigated
as an antidiabetic agent using a 2-deoxy-glucose (2DG) technique showing good stimulatory effect
on glucose uptake in differentiated C2C12 myocytes with % 2DG uptake ranging from 110–180% that
was comparable to the positive control insulin. Three compounds were isolated and identified using
bioassay-guided fractionation of the spray-dried aqueous extract of S. birrea leaves: myricetin (1),
myricetin-3-O- -D-glucuronide (2) and quercetin-3-O- -D-glucuronide (3). Their chemical structures
were determined using NMR and mass spectrometric analyses, as well as a comparison of experimentally
obtained data to those reported in the literature. The isolated compounds (1–3) were studied for
their stimulatory actions on glucose uptake in differentiated C2C12 myocytes. The three compounds
(1, 2 and 3) showed stimulatory effects on the uptake of 2DG in C2C12 myocytes with % 2DG uptake
ranging from 43.9–109.1% that was better compared to the positive control insulin. Additionally, this
is the first report of the flavonoid glycosides (myricetin-3-O- -D-glucuronide) for antidiabetic activity
and they are the main bioactive compound in the extract responsible for the antidiabetic activity. This
result suggests that the S. birrea leaves have the potential to be developed for treatment of diabetes.The Department of Science and Innovation, South Africa, University of KwaZulu-Natal, South Africa and Biomedical Research and Innovation Platform, South African Medical Research Council.https://www.mdpi.com/journal/moleculesam2023Chemistr
Performance of highly sensitive cardiac troponin T assay to detect ischaemia at PET-CT in low-risk patients with acute coronary syndrome: a prospective observational study.
Highly sensitive troponin T (hs-TnT) assay has improved clinical decision-making for patients admitted with chest pain. However, this assay's performance in detecting myocardial ischaemia in a lowrisk population has been poorly documented.
To assess hs-TnT assay's performance to detect myocardial ischaemia at positron emission tomography/CT (PET-CT) in low-risk patients admitted with chest pain.
Patients admitted for chest pain with a nonconclusive ECG and negative standard cardiac troponin T results at admission and after 6 hours were prospectively enrolled. Their hs-TnT samples were at T0, T2 and T6. Physicians were blinded to hs-TnT results. All patients underwent a PET-CT at rest and during adenosine-induced stress. All patients with a positive PET-CT result underwent a coronary angiography.
Forty-eight patients were included. Six had ischaemia at PET-CT. All of them had ≥1 significant stenosis at coronary angiography. Areas under the curve (95% CI) for predicting significant ischaemia at PET-CT using hs-TnT were 0.764 (0.515 to 1.000) at T0, 0.812(0.616 to 1.000) at T2 and 0.813(0.638 to 0.989) at T6. The receiver operating characteristicbased optimal cut-off value for hs-TnT at T0, T2 and T6 needed to exclude significant ischaemia at PET-CT was <4 ng/L. Using this value, sensitivity, specificity, positive and negative predictive values of hs-TnT to predict significant ischaemia were 83%/38%/16%/94% at T0, 100%/40%/19%/100% at T2 and 100%/43%/20%/100% at T6, respectively.
Our findings suggest that in low-risk patients, using the hs-TnT assay with a cut-off value of 4 ng/L demonstrates excellent negative predictive value to exclude myocardial ischaemia detection at PET-CT, at the expense of weak specificity and positive predictive value.
ClinicalTrials.gov Identifier: NCT01374607
Determination of the and Mixing Angle from the Pseudoscalar Transition Form Factors
The possible range of mixing angle is determined from the
transition form factors and with
the help of the present experimental data. For such purpose, the quark-flavor
mixing scheme is adopted and the pseudoscalar transition form factors are
calculated under the light-cone pQCD framework, where the transverse momentum
corrections and the contributions beyond the leading Fock state have been
carefully taken into consideration. We construct a phenomenological expression
to estimate the contributions to the form factors beyond the leading Fock state
based on their asymptotic behavior at and . By taking
the quark-flavor mixing scheme, our results lead to , where the first error coming from experimental
uncertainty and the second error coming from the uncertainties of the
wavefunction parameters. The possible intrinsic charm component in and
is discussed and our present analysis also disfavors a large portion of
intrinsic charm component in and , e.g. .Comment: 18 Pages, 3 figures. Several references added. To be published in
EPJ
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