Science topic

Radioactivity - Science topic

Radioactivity is the spontaneous transformation of a nuclide into one or more different nuclides, accompanied by either the emission of particles from the nucleus, nuclear capture or ejection of orbital electrons, or fission. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
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Based on my sources gallium 68 undergoes a beta + decay. I've read that if an isotope has "too many neutrons" it undergoes beta - decay; if it has "too many protons" it undergoes beta + decay. Initially, I thought: "gallium 68 has 31 protons and 37 neutrons, so it has too many neutrons" (comparing it to a 1:1 ratio). But, if that was the correct reasoning it should undergo a beta - decay.
Therefore, I'm now thinking that to establish if a nucleus has "too many neutrons" or "too many protons" you have to compare it to the most stable isotope (could that be it?!). If we take the most stable isotope (gallium 69) as a reference:
Gallium 69: 31 protons and 38 neutrons;
Gallium 68: 31 protons and 37 neutrons...
...then we can say it has too many protons (that is, compared to the ratio found in the most stable isotope). Is that right or what am I missing?
Thank you in advance!
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You should add to the rule "too many n" and "too many p" the words "compared to the stable isotopes of the same element", i.e. 69Ga and 71Ga.
But this remains a gross rule. Some nuclei with "too many protons" undergo electron capture , not beta+ decay.
The exact rule allowing beta+ is that the mass of the parent 68Ga is higher than the sum of the masses of the progeny 68Zn + 1 positron.
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Since all the nuclie of Radioactive isotope have the same energy, I would like to know why they decay randomly and not all of them decay in the same time.
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Neutrons and protons, like electrons in the atoms and molecules, behave randomly, although following probalistic rules, as it is the case for all processes at atomic and nuclear scale, that are described by the probalistic laws of quantum physics.
Thus the radioactive transformation occurs randomly. Even if they have the same composition and energy, two nuclei of the same radioactive nuclide are never in the same internal configuration.
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Since it is not possible to utilize radioactive anymore, I would like to know if there are other validated ways to perform cholesterol absorption assay in vivo in mice.
Thank you.
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you can use biomarker techniques which is the same as scintigraphy and see the cholesterol pathway
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Suppose a lab experiment gave evidence that the DNA or RNA code for bacteria are stored in radioactive chemical atoms, because the atomic decays are followed by the appearance of protozoa in a test tube of sterile chemical building blocks. Would this be an evidence for a cosmic mind that formed the atoms containing these genetic codes?
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Phylosophically, concept of God lies outside of science. The 'cosmic mind' cannot be thought as God e.g. imagine if we now seed life on another planet and latter the creature involved there will discover that - that would not make us God..
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Question related to materials development technology...
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A quick glance at 238 nucleonc each having binding energy of about 8 MeV
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  • radioactivity conversion
  • gamma emmitters
  • Bq/g to ppm
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With C = activity concentration in Bq/l, volume V[l]= Mw mass of water in kg
and MCs= mass of Cs137, Avo= Avogadro number 6.02*10^23 atoms/mol
Atm= atomic mass 137 g/mol , T1/2 in sec
activity = C * Mw[kg] = ln2 *MCs[mg] * Avo / (T1/2 * 10^3 * Atm)
ppm = MCs[mg]/Mw[kg] = C[Bq/l] * T1/2 * 10^3 * Atm / (ln2 * Avo)
A very low concentration indeed, even for a high activity.
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Staff handeled with radiation related job need to be investigated indeed
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To measure radioactivity in the human body it is necessary to have a good radiation shielding around the detector and the subject. The shielding is in this case built of massive steel stabs of naval armour- plate forming an iron room The iron room is ventilated with filtered air.
as a result the detector is sensitive to gamma-radiation with energies above 50 Kev and supplies information about the energy of the gamma photons, which makes it possible to identify the gamma emitting isotope measured by the spectroscopy. A certain hour measurement offers the possibility of detecting of a 100 % gamma emitting isotope distributed in the nail at the gamma energy is above 50 Kev.
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In the autoradiography experiments in which tritiated compounds are injected, nuclei of cells use to appear electrodense. But I am not sure if this means that the nuclei incorporated the label or that nuclei appear black (as a radioactive background) when you take the radiography.
I attach a paper as an example. The researchers injected tritiated methionine intraperitoneally in rats and assessed its incorporation in the cells of the retina.
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The purpose is to look incorporation and metabolism of an exogenous lipid. So yes, isotope labeling can be used. I guess that in this case, you have to mark the C atoms.
Anyway, now there are fluorescent lipids commercially.
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I am working on a study to evaluate the content radioactive isotopes in agricultural soil. I have the concentrations of Th232, U238, Cs137 and K40 and I want to know if the concentration is harmful for crops and humans or not.
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Following a nuclear disaster, people in the fallout zone should eat stable iodine to prevent their body from absorbing radioactive iodine. All current recommendations are based on a 1- or 2-dose regime.
You take 1 or 2 doses, total, no matter how long you are exposed to radioactive iodine.
However, the same sources also say that 24 h after taking iodine, the protective effect has fallen to 70%. 48 hours after intake, the protective effect is only 25%. [1]
Logically, you should continue taking stable iodine for as long as you are being exposed to radiactive iodine, but I can't find a single source anywhere with long-term dosage information.
Does anyone know where I can find out more about appropriate doses over weeks, or months of exposure?
[ref 1]
Zdenko frani; Iodine prophylaxis And nuclear Accidents; Institute for medical research and Occupational health, zagreb, Croatia; Received april 1999
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All the methodolgies for dealiing with the intake and discharge of radionuclides in the human body seem to be derived from ICRP Publication 2 (1959), URL: https://journals.sagepub.com/doi/pdf/10.1177/ANIA_OS_2_1 . But this document is only for continuous occupational exposure: 40 hours/week, 50 weeks/year for 50 years, and the compartmental models of the organ systems are very crude.
But to your contention about being the last person out, let me say this. You need to distinguish between a Three Mile Island event versus a Chernobyl event. In a Chernobyl-style event, where the core melts and the graphite moderator catches fire and the resulting smoke leaves through the wreakage of the reactor building caused by the explosion, the least of your worries will be exposure to I-131 as the smoke will be filled with radioactive metal oxide particles, which, when inhaled, will be lethal. In comparison, the Three Mile Island event, even though it damaged the core, did not breach the reactor vessel nor the containment building; in the Chernobyl event, not only was the lid to the reactor vessel blown away, but there was no containment structure just a flimsy reactor building, which was easily breached by the expolsion.
Regards,
Thomas Cuff
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Dear researchers,
I would like to simulate the activation-transmutation reactions occuring in a steel during high-energy proton irradiation. Furthermore, I am also interested in simulating the radioactivity from the irradiated specimens during cooldown and the time required for safe handling of the specimens.
Which application / code is best applicable for these kind of calculations? Also, it would be better to have comments on the advantages and limitations of these packages.
Thank you for your support.
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You may also want to check Fispact-II. This code does not require geometry simulation so it can be on the conservative side. It is similar to SCALE's Origen but FISPACT-II provides the ability to include protons. Additionally, the stand-alone ORIGEN will help you only if you know the radionuclide concentration right after the irradiation has ended. As far as I know SCALE is about neutrons/photons. I hope this helps.
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The use of environmental tracers that are relevant for groundwater and surface water interactions constitutes a powerful tool for understanding the source, flow and mixing dynamics of water resource systems through their imprint on the system.
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Tracers were used to quantify rechages of SAS (Saharian System Acquifer) al almost fossil acquifer.
Informations about SAS are provided in our two books:
(6) Sécurité Hydrique de la Tunisie, Gérer l'eau en conditions de pénurie | Request PDF (researchgate.net)
We are allowed to communicate copies of the book in french in the scientific sphere, just request on my RG page. Unfortunately, we are not allowed to do so with the English book
More resources on water resources in the arid zone can be found on the following projects referenes:
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I am looking for joining research team working on natural radioactivity measurements and applications. Any suggestions are very welcome.
Regards
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I'm interested. We can do a review in NORMs; (Whatever it's type)
Everyone will do a task in it.
Those who are steady can contact with me through the email:
📷
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Hi,
I am trying to study the effect of my inhibitor in transcription initiation in a viral RNA polymerase.
My time points have to be from 15 sec to 10 min and I have to take samples every 15 sec for first 1 to 2 minutes. Hence it is not possible if I use a radioactive isotope to measure the reaction.
I was wondering if there is some non radioactive method to visualise IVT in real time.
Thanks for the answers
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thanks
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we can not to use radioactivity more, and we are looking for a kit that we can use to labeled the specific dna to find and confirmed a mutant fungi strain.
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This is one that I can think of. Hopefully it will help.
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As is known, high radioactive plutonium is produced as a waste product from the rods in nuclear power plants (which needs to be stored subterranean for thousands of years): What are the means (or current efforts/researches) to reuse this plutonium as a source to generate energy, instead?
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Plutonium isotope such as Pu-293 is a fissile, so can be harvested, then recycle to be used as fuel. Some reactors have fuel assemblies where, there is space on the upper part of the fuel rod, which allows isotopes produced such as Pu-2393 to occupy the region, thus act as the new fuel. Of course there are downsides.
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I want to analyze the radioactive trace content of leaf and rock sample. How do I prepare the leaf and rock samples before taking it to laboratory for analysis and which of the device (method) should I use for the analysis?
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The answer of Dr wael badawy is complete. Nothing can be added to his answer. However, in case of using gamma ray spectroscopy, one will need a large quantity of the samples prepared. This will depend on the level of radioactivity. The lower the radioactivity, the larger the quantity samples needed.
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When measuring gamma spectra from the decay of a radioactive nucleus, I observe 3 peaks in the spectrum. The databases indicate that during the decay of this nucleus, there are only 2 lines that lie in a cascade. The third observed peak is cumulative and is approximately 10% of the first or second peak. What is the possibility of dividing the third peak into contributions from the first and second transitions?
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I guess you talking about something like Co-60 1.17+1.33 = 2.5 MeV.
That comes to probability of detecting both gammas. E.g if you bring the detector closer the fraction of the events in combined line will relatively grow . Note that there might be or is (at least in case of Co-60) angular correlation/anti-correlation of emitted gammas.
So in simple case if you detect first gamma (as photopeak not Compton partial event) with probability a1, the second one with a2 the fraction of of combined line over total photopeak events will be simply a1*a2 /(a1+a2+ a1*a2). Note that some 'pot' or 'well' type gamma detectors may have a1,a2 approaching one for some cases.
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I want to know if I need to do anything to the cells before I can use the equipment mentioned in my question when the cells are still radioactive due to treatment with radioactive molecules?
Will it cause damage to the equipment?
Will I need to wait for the radioactivity to be below detection level before I can use the equipment?
Thank you
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Using flow cytometry in the study of cells treated with radioactive isotope, it is possible that some of the radioactivity will remain on the tubes and nozzle. Therefore, you need to know the methods of dosimetric measurements and methods of cleaning radioactive substances from the surface. You must obtain a special work permit from the owners of the device. The same applies to fluorescence microscopy.
If you do not do this, then you need to wait for the level of radioactivity to subside. But how long it will take depends on the half-life and the amount of radioactive material.
I wish you success!
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Above your imagination, is there really an increase in the radioactivity of natural radioactive isotopes in the sewage water of hospitals. And if it is in studies or research, I hope you send it to me to benefit me in my study
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For the detection of ionizing radiation, germanium detectors are most often used, they are widely used in gamma-ray spectroscopy due to their high resolution and high detection efficiency compared to their analogues. An increase in the radioactivity of natural radioactive isotopes in hospital wastewater is observed due to the use of radioisotopes in the diagnosis of diseases in hospital patients.
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Is there a change in the radioactivity before the sewage sludge treatment and after the treatment?
I wish to provide me with research and studies on the subject
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It depends on what sewage sludge contains before treatment and after treatment. For example, if the activity level was high, then depending on the sewage sludge treatment method.
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How to measure normal radioactivity in phosphate fertilizers by examining gamma spectra
Does the resulting radioactivity be large? Are there studies on the subject? I hope to provide them with them as they are useful to me with my studies
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the two P isotopes you mentioned above are 32P and 33P ; you are right, they are beta emitters. Their half-lifes are 14,3d (32P) and 25,3d (33P). All other radioactive P istopes have much smaller life-times. In consequence all 'natural' radioactive P isotopes will have been disappeared since their birth in an exploding star. The natural abundance of the stable 31P is 100%.
So there is no necessity for Nibras Seed to set up a 'beta spectrometer'.
I agree with you to use a HPGe detector for the acquisition of a gamma spectra, to have best energy resolution for the elemental identification of the gamma emitters in the sample.
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I know that it detects radioactivity in the area by reading the concentrations of Uranium, Thorium and Potassium. So if it depends on the radioactivity of these 3 radioelements, can it be used to detect skarn deposits, even though some skarn deposits have low radioactivity
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Khaled Ali Thank you for this informative source
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We have been using HPGe detectors for evaluating the level of natural and artificial radionuclides in different kinds of environmental samples. Parallelly, we also provide radioactivity testing services to ensure that there are no consequences triggered due to the consumption of highly radioactive food materials. We usually use certified reference material (CRM) collected from IAEA for calibration, performance evaluation (PE), method validation (MV), and QC. We are planning to collect a CRM of milk powder spiked with Cs-137...but could not find it anywhere? Could anyone of you please help me find it? It is urgent for us as we are working on getting ISO17025 accreditation by this year.
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Bergonie-Tribondeau's law based on experimental observations in rat testes applies at cellular levels (albeit with various exceptions such as lymphocytes, some gonadal cells, AT cells, and SV40-transformed cells), but less generally at tissue or organism levels. Younger people are not necessarily radiosensitive than older people where dependence of radiosensitivity on age (e.g., age at exposure, attained age) greatly differs by endpoints (health outcomes). For instance, children are more radiosensitive than adults for about 25% of cancers (e.g, leukemia, thyroid, skin, breast and brain cancers), as detailed in
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I measured the dose rate at different distances for different radioactive samples.
How can i calculate the uncertainty in the activity from these measurements?
I calculated the activity from the equation stated below;
H= 1.5*10^-15 * A * E * n *B * exp(-mu*d) / r^2
- H = [Sv/h]
- 1.5*10^-15 is a conversion factor
- A the Activity [Bq]
- E the energy of Cobalt60 with corresponding n the number of photons/desintegrations
- B Buildup factor of shielding material
- exp(-mu*d) the attenuation factor of the shielding material
- r distance from the sample [m]
I can plot H versus r , is it possible to just use the uncertainty of the distance and measured H here, or should i implement the different theoretical factors to obtain the uncertainty in A?
I hope it is a clear story, if not let me know.
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Mathematically, if your independent parameters are H, r, C=1.5e-15, E, n, B, M=exp(-μd), and their uncertainties are ΔH, Δr, ΔC, ΔE, Δn, ΔB, ΔM, then
A=H r^2/(C E n B M)
(ΔA/A)^2=(ΔH/H)^2+(2*Δr/r)^2+(ΔC/C)^2+(ΔE/E)^2+(Δn/n)^2+(ΔB/B)^2+((ΔM/M)^2).
You need all uncertainties of the parameters used for determining A.
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I'm wondering how multiple sources can be calculated. Are there any standard rules for this, like specific addition or subtraction or averaging rules?
To given an example; different point sources relative close to each other. Let's say a distance of 10 cm between two sources, with activity A and B. And now i measure the dose rate somewhere in between those points. Are both sources contributing equally if A=B, and thus the total activity is A+B or do i have to average it.
I hope it is clear what i'm wondering, if not let me know
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Hello.
The answer is not so simple as it may seems.
Firstly let's make an experimental setup clear.
- Lets suppose we are talking about a laboratory experiment (not some kind of outdoor measurement)
- radioactive sources are point-like and solid-state. (I.e. with no self absorption, no diffusing or flowing gasses or liquids, with no affinity to aerosols)
- it is an isotropic radioactive source without beam collimation
- radioactive sources are relatively close to each other (lets say 10 cm as you suggested)
- there is a standard atmospheric air between the radioactive sources, free of 222Rn and filtered for aerosols
- lab is perfectly shielded from surrounding environment and cosmic rays
- construction materials of experimental setup are free of radioactive isotopes
Then the measured activity of low radiation samples may strongly depend on where exactly is "somewhere in between".
First of all, isotropic flux of particles of photons (in vacuum) decreases as square of distance from source.
Flux of particles at particular point in space filled by some medium (air) depends on ability of particles to penetrate it. For example alpha particles are a highly ionizing form of particle radiation and can be completely stopped even by a few centimeters of air (depending of alphaparticle energy).
Therefore, it is extremely important to know the details about the experiment to design the setup properly.
Bye, JS
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The construction of the basins in the isotope treatment hospitals must be at a certain depth from under the ground .. to prevent the radioactive leakage of water .. I hope to provide me with sufficient information about the isotope treatment hospitals for cancer patients and how the radioactive water is treated .. Inside the basins and what international standards are To build these ponds
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سؤال جيد ومهم
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I am making a simulation of energy deposited of some radioactive sources in scintillation detector. I have some results, but I don't have the same distribution energy between experimental spectra and simulated spectra. I do not know why.
For instance, the spectra of Cs-137 is shown. However, it does not have the same resolution.
Someone who can help me how to improve the simulation.
The scintillation detector is of NaI:Tl.
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The most significant difference is the width of the photoelectric peak at 662 keV. This width occurs after gamma-ray energy is transferred to the scintillator crystal. Your simulation probably may not include this part.
The number of scintillation photons generated, when 662 keV is totally absorbed by the NaI:Tl crystal, is statistically distributed. It is also a stochastic process whether each scintillation photon is successfully detected by a photodetector (photomultiplier tube or semiconductor device) or lost.
There are two ways to improve the distribution. One simple way is to assume the energy resolution of the detector (crystal + photodetector) and perform a convolution with your results. You can fine the typical energy resolutions in literature: typically ca. 7% [*].
Another detailed method is to add, if necessary, simulation to track the behavior of the scintillation photons.
The other differences seem to be related to Compton scattering; since the NaI:Tl crystal is sealed in a package, some of the energy may be lost by Compton scattering in the package before it enters the crystal. Then, the gamma-ray energy is not 662 keV but less than 475 keV for the detector. Similarly, Compton scattering from surrounding desks, walls, and other objects may enter the crystal and increase the proportion of that component of the experimental data.
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I am trying to characterize the release kinetics of a small molecule from alginate beads. The small molecule is very simple and very challenging to detect with methods other than mass spec . To avoid using MS since it is expensive, I am considering getting a radiolabeled version of it and detecting it. I'm deciding between a 14C version and a 3H version. No one in my lab has extensive experience with radioactivity and I am unsure of some things that might be obvious for people who work with it extensively. For instance, are you supposed to mix the radiolabeled version with the normal small molecule and, if so, how do you know how much to put in? I'm also wondering what the lower limit of detection for each would be and how to detect the concentration. I've read a bit about liquid scintillation counting but is that the only method or are there plate readers that work for radioactive substances. I'd appreciate any input on the topic as I feel a little lost. Thank you!
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Hi,
when you use radiolabeled solution you can use the Liquid Scintillation counting to detect the signal, and this method is very good and with high-quality skills, such as very good sensibility, in some case very easy sample treatment...
In my opinion, you should consider:
- H-3 or C-14 or other radionuclides (such as Iodine, 125, 131 or 129, Luthetium 177): what is the chemical behavior that you needed? H, C, or other, what is the best solution for your molecula?
- Kind of emission from radionuclides: beta? Alpha? EC or x/Gamma? You speak about H-3 and C-14, beta emitters, with respectively low energy and medium-high energy. LSC is the best to measure beta emitters in liquid samples.
- How much Bq do you need? Before starting with the measure with LSC, you should know the MDA that you can have with the blank sample. When you have this information, you can know how much Bq of radiolabeled solution use, or how much cost the experiment.
Be careful, there are a lot of LSC's instruments...but they are not cheap.
Maybe here you could find some info:
te_1528_web.pdf (iaea.org)
or
46135125.pdf (iaea.org)
Best Regards
Mattia
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Hello,
In part of my project, i have to extract cell nucleus after cells lysis in order to measure nuclear radioactivity and also cytoplasm+membrane fraction radioactivity.
For this, it is important to check if my cytoplasm+membrane fraction and nuclear fraction are pure.
Would you have a check technic to advise me on how to do it ?
Thank you
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Subcellular fractionation can be done using a series of specific extraction buffers (e.g., for nuclear, cytoplasmic, membrane): typically within 2 hours when commercially available kits are used. “Purity” of yielded fractions can be checked, e.g., by western blotting for compartment specific marker proteins.
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Dear colleagues!
How to write the source card (sdef) if I know the neutron spectrum flux of this radioactive source?
Thank you!
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use like this
sdef erg=d1 ....
#si1 sp1
....
add spectrum energy and spectrum probability
if have more problem contact me
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Hi all,
I have a personal question about the safety of working with Radioactive Sulphur. I am planning to start pulse-chase labeling experiments to study protein synthesis. Sulphur-35 is a low energy beta emitter. I'd like to know if anybody has any inputs on working with Sulphur-35 while pregnant: is it dangerous? Is it okay? Risks for the fetus (I am not pregnant right now, but would like to know the risks just-in-case). Any inputs will be greatly appreciated!
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Hello Dear... to be safe you must be using dosimeter for beta detection like Liquid Scintillation Detectors and you should be known there is no zero risk with RADIATION
Dose rate to the skin at 10 cm: 625 mrad/hour/mCi (for an unshielded point source)
Dose rate to basal cells from skin contamination of 1 mCi/cm2: 1460 mrad/hr
Shielding: None needed, when used in millicurie quantities under normal laboratory conditions
Annual Limit on Intake (ALI): 10 millicuries via ingestion for most compounds of sulfur. The intake of one ALI will produce a dose of 5 rem.
Detection
Wipe surveys using liquid scintillation counting is the preferred method for detecting S-35. Most G-M detectors are not likely to detect the presence of S-35 in amounts less than about 100,000 dpm (0.05 µCi).
Precautions
35S-labeled methionine/cysteine compounds can volatilize. Stock solutions and thawed materials should be opened within a fume hood. Activated charcoal can be used to trap contamination within equipment such as incubators. Contact EHS for further information.
Low-level S-35 contamination cannot be easily detected with a G-M meter, and special precautions are needed to keep the work environment clean. The regular use of wipe testing, using a liquid scintillation counter, is the only way to insure that the work space does not contain low-level removable contamination.
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In my early education I was taught radioactive decay was - in general - not affected by environmental variables. This seems to have been disputed in recent years. I'm curious about the current state of the debate. Are there good reasons to think radioactive decay rates are affected by environmental variables?
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Yes
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Hi,
I have an issues with identifying a radioactive sample from pegmatite mine. I was guessing is Allanite by the look at the field and it has pretty high concentration of Uranium Thorium, however the Raman cant identify it. I have 20 other samples which are not Radioactive and it is just works fine. But with this sample is eater fluorescence, or it s identify the material impossibly wrong. Also the most important is that it hits a big hole in the sample. Especially when I try to identify some white crystals. The whole is slightly bigger than the leser width but it also creates spiral like cracks in a 3x bigger radius. Can someone explain why is that happening? or is there anything to do with radioactivity? I heard that raman is perfect for uranium identification, maybe I use the wrong settings?
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Radioactivity should not matter. Break the sample into smaller parts.
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Q and A are parameters used for standardization and safety of drugs in pharmacology. Quality assurance is an integral part of traditional medicine, which certifies that it delivers the required quantity of quality drug. The standardization parameters are authentication, foreign matters, organoleptic evaluation, microscopy, volatile matters, extractive values, ash values, radioactive contaminants, microorganisms, pesticide residue, refractive index, chromatographic profiles and marker components.
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Q and A are parameters used for standardization and safety of drugs in pharmacology. Quality assurance is an integral part of traditional medicine, which certifies that it delivers the required quantity of quality drug. The standardization parameters are authentication, foreign matters, organoleptic evaluation, microscopy, volatile matters, extractive values, ash values, radioactive contaminants, microorganisms, pesticide residue, refractive index, chromatographic profiles and marker components.
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a sample is a piece from a fuel element containing fuel exposed in nuclear reactor. We cut transversely the fuel element. what is happen with spectrum if the uranium emit gamma rays?
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you can do this. I assume that there is no Uranium in the sample iself.
So the sample will not still emit x-rays or gammas due to Uranium radiation.
Nevertheless you should perform two measurements:
a) perform EDX analysis with electron or x-ray beam OFF ---> spectruma
b) perform EDX analysis with electron or x-ray beam ON ---> spectrumb.
your net EDX spectrum will be netEDXspectrum = spectrumb - spectruma.
Please take care that the measurement times are equal.
Good luck
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will i require a collimator for investigation of gamma attenuation or the same experimental set up can be performed for both gamma attenuation and radioactivity check .I am using gamma ray spectrometer us using Nal(Tl) detector
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Yes I agree with Steven
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Is it true that naturally occurring radioactive material from a specific type of rock is the same?
For example the gold-bearing rock in Australia and that from Tanzania.
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Thank you Samwel and Joseph for your answers.
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I want to make radio-active source in G4PrimaryGeneratorAction.cc class. How to do?
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Mikhail Demichev could you recommend how to load Pu-Be spectrum to particleGun and which format ?
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Leucine uptake assay is widely used for bacterial production. But I have three concerns (1) Why Leucine (not other amino acids) is used and (2) In case of environmental samples, Leucine may be present in water and in that case, how to say that Hot leucine (radioactive Leucine) was only incorporated into the bacterial proteins or how to negate the uptake of environmental leucine from incorporation? (3) Does all proteins incorporate Leucine in case of bacteria?
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Agood question and best answer of Nobuyuki Hamada
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Hi there,
I'm currently performing cytotoxicity tests using Chromium 51 (PerkinElmer) with a half-life of 27,7 days, let's say 28 days. If I have to add 21ul of the product to label 1x10*6 cells with 100uCi, how much product do I have to add to the same amount of cells to obtain the same effect 3 weeks later?
I think it is 21ul + (3/4)*21ul = 36,75ul
Is this calculation correct?
Thanks!
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You do not have to take only in consideration the hall-life but also the fact that radioactivity is more diluted. In real life I would add the initial 21 microliters in the smallest total volume and add 2 micrometers one day after calibration date ( written on the recipient) , 4 micrometers 2 days after calibration day, etc....
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its atomic number is not too high. So what kind of mathematical or physical constraint on its nuclear structure breaks it so easily? Why doesn't it have any natural stable isotope?
If it's one isotope with nearly equal neutron and proton number be produced, why that would not be stable?
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The detailed answer is complicated. Basically, the stability of nuclides depends on their number of protons/neutrons and some configuration are more stable then others (analogue to electronic configurations in the atom). So it turns out that all configurations with 43 protons either decay in Mo (42) or Ru (44) because both these elements have a lot of stable isotopes.
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The worldwide average natural dose to humans is about 2.4 mSv per year. Some areas with sizable populations have much higher than average background radiation levels. The highest are found primarily in (Guarapari, Brazil; Kerala, India; Ramsar, Iran; Yangjiang, China) and are due to high concentrations of radioactive minerals in the soil. What technique should be used to determine the possible long term health effects for the people living in these high natural background area ?
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The impact of low dose radiation has been studied for many years and I would recommend you look up all the work that has been generated by the "low dose program" led the Department of Energy (DOE) in the US. The Europeans have been doing a lot of work on low-dose research (http://www.melodi-online.eu/).
The ideal monitoring should involve not only a good dosimetry on site, but a population follow-up for epidemiology. As you search the literature, you will find two different philosophies:
1. the LNT model (Linear No Threshold), which assumes there are no safe level of Ionizing Radiation and cancer risk is proportional to the accumulated dose
2. the threshold model, setting a value below which radiation is fully repaired and harmless for normal individual. In this latter model, the dose rate becomes a difficult parameter to track and regulatory agencies have used the LNT mainly for practical reasons, but it can lead to unnecessary and costly regulations.
The threshold idea (point 2 above) has gained momentum over the past decade and various studies suggest there is a strong genetic factor predicting the response in the dose rate range, with some individual benefiting from low dose rate whereas other suffering from hypersensitivity. Therefore, I would argue a good epidemiologic data should be done in conjunction with genotyping the population exposed in these high background area and tracked as a function of dose rate and accumulated dose. Of course, nutrition and life style are other confounding factors that must be tracked as well. As you can guess, such experimental design would be highly costly and probably require the cooperation of local government to help. There is still so much to learn from ionizing radiation...
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What's the oxidizing agent better than chloramin- T can used for labeling compound by radioactive iodine?
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Iodo-bead which consists of oxidant N-chlorobenzenesulfonamide is better agent then chloramine-T method, because labelling efficiency via idobead is achieve almost 99% while with chloramine-T method labelling efficiency is 90%.
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Hi,
I am doing a pulse chase assay following radioactive methionine/ cysteine uptake. Over time I see processing of protein (67KDa to 45 KDa) following pull down with anti-HA coated magnetic beads (my protein is tagged with HA at the C-term end). Along with the signal at the correct spots, I see very strong signal at the very bottom of the gel. I wonder what could this be? Any comment would be greatly appreciated. I am attaching a picture of my autoradiograph.
Thanks
Sumit
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how are you staining? how are you running your samples? these are often the 25kDa light chains.
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I am planning to study global protein synthesis levels in presence and absence of certain chemical compounds. I know that the gold standard for this purpose is the S35-methionine pulse chase labeling. However, I am not so enthusiastic about working with radioactive chemicals when there are nonradioactive alternatives available these days. I've come across the Click-iT HPG/Alexa Fluor Azide and Click-iT AHA/Alexa Fluor alkyne assays from Thermofisher.
Are there any other fluorescence based assays available to determine global protein synthesis (quantitatively) preferably a nonradioactive way and something that I can simply measure in a cellplate reader? Thank you!
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I follow.......
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We have a shrimp sample from IAEA for proficiency test and as per the requirement of IAEA we want to identify and quantify radioactivity in that sample. We have taken a sample count for 90000 sec.
Suppose we got the gross count for K-40 (1460.822 keV) is 1.03E+04 with an area uncertainty of about 121.69.
Before the measurement of the sample, the gamma background at laboratory site was determined with an identical empty plastic container used in the sample measurement.
The background gross count for 1460.822 keV was found as 8.71E+03 with an area uncertainty of about 111.49. We can easily calculate the net count rate from the mentioned information.
But my question is how to calculate Net count rate uncertainty.
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The background count with the empty container is not the background of the sample. The sample background is altered by the sample matrix and contributions to the K-40 ROI from other radionuclides in the sample. The K-40 background of the sample must be determined from the sample spectrum. The variance of the net count is the sum of the variance of the determined net and the variance of the determined background. The uncertainty is the square root of the sum.
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Bonjour
Je travail sur les eaux thermales de la région ouest d’Algérie sur leur qualité physico-chimie_chimique et bactériologique et voudrais avoir une idée sur la qualité radiologique de ces eaux.
Les régions d’études : Saida, Mascara et Tlemcen
Merci d'avance
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Bonsoir Monsieur
j apprécie beaucoup votre intervention,
et voudrais avoir une documentation sur ce sujet, même en dehors de mon territoire d’intérêt, si c'est possible bien sure . MERCI
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Dead time varies depending on different HPGe detectors. What maximum dead time should be allowable to determine accurate radioactivity?
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Be aware that the dead time given by your multichannel analyser is the dead time of the MCA itself, i.e. the percentage of incoming pulses that were not analyzed. With this number it is possible to correct the quantitative results.
Of course a high MCA dead time comes from a high count rate, and thus may also mean a high detector dead time, or more exactly a high dead time for the couple detector+amplifier(s), as the amplifier usually modifies the shape and duration of the detector pulses.
The high count rate leads to high pile-up rate, with a distortion of the spectrum, generally a loss of resolution, but also a loss of events, especially in the peaks.
Thus both the energy accuracy and the quantitative accuracy can be affected.
Going into the details, the problem is not simple, and can also depend on the radiation source and its geometry (are there emissions in coïncidence or not?). I would suggest an experimental approach, testing the resolution and the peak-to-total ratio for various configurations with low and high count rate.
In my modest opinion and experience, 10% is already high for accurate measurements with a HPGe detector, but the main uncertainty often comes from the activity of the reference source you use.
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Radiosurgery, the therapy of brain tumors, has long been made using a so called Gamma Knife with high activity sealed sources such as Cobalt-60. Nowadays the therapy can also be made with a linear accelerator such as a Cyber Knife. What are your experiences? Can you share advantages and disadvantages of each system. At the end do you think that the use of radioactive sources is still (medically)justified for radiosurgery given the alternative of a Linear accelerator?
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Linear
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After the three big nuclear accidents (TMI, Chernobyl, Fukushima), radiophobia has become one of the most difficult obstacles to using nuclear energy. While many attempts have been made to resolve this issue, such as providing information and education on nuclear energy, the radiophobia seems to get even larger in some countries as time goes by. Under the circumstances, what do you think would be the best way to reduce the public's fear of radioactivity?
Refer to the following two articles that provide comprehensive knowledge on the public's perception of radiation and its risk:
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I would suggest that those of us that care about these issues use appropriate language ourselves. We should not refer to the accidents as "disasters". I am not trying to whitewash the the risks but the three that are always talked about were not disasters in comparison to the deaths that happened with the tsunami is Japan. The tsunami kill almost 20k. The evacuation of people due to radiation phobia killed almost 2k. The nuclear accident killed zero and will probably kill no one in the long run from radiation exposure. We need to tell the truth and stop allowing the anti-nuclear groups to control the dialog and tell lies about what happens when an accident occurs. In no case should we downplay the risks but present them in terms of the risk compared to other risks. We should help other understand what the risks are from using other energy technologies and compare them fairly. Recent studies of experts in various fields show that sometimes the experts don't have the full set of facts and are thus timid to speak out. I was in this group until recently until I took the time to study it out. I now have a very large bibliography of good data to support my statements and I can speak with boldness on these issues. I am glad to share what I have learned. I give public talks on energy technologies and their impacts on society and the environment. So far the talks have been are well received and many people tell me that they appreciate being told the truth so that they can be informed citizens.
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I have solution of two different salts with different solubility. How to separate them by cristallisation in range of volume 500 microliter? One salt is in bulk scale, in hundrets of milligramms, another salt is no carrier addad amount of radioactive material, it means 10E-7 gramms, approximately. The main problem is for me the remaining amount of activity on the surface of the wet cristalls.
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tanks, guys!
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Hi ! Dear all !
Put in place mine exploitation or exploration has impact on environmental security (human being, croads or vegetation, animals etc). Environmental exposition by naturally occurring radioactive materials (NORMs) because of this activity must be the great worry. Is there any right norm or right technological process that can safe health in the environment where explotation of mine has put in place. Thanks for your answer !
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Is important to show to the mineral industries that to protect the environment is a question of survival for them. Each accident is a disaster for all, i.e, the owners, the population and the environment lose. While the owners do not open their eyes to this problem there will be many catastrophic accidents with their consequences. Technology can help but this never will be enough.
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please I am looking for someone who can help me for interpretation of the results of radioactive isotope analysis in thermal waters ..
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If you want to remove Radium isotopes. There is some recommended methods for removal and separation of radium. Among of these methods, ion exchange and chemical precipitation method as sulphate in presence of barium (as carrier). I wish this answer will help you.
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I'm trying to tag a type of WBCs and then inject them to mice and track the cells to see were they sit after 12-36 hrs. I now luciferases and radioactive isotopes are two of my options but i wanted to know if I can use any of fluorescent dyes such as MitoTracker deep red with Excitation⁄Emission (nm):644⁄665 orrr?
Or any other suggestions?
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Don't know.
Have a look at reports on human tumour transplant studies in nude mice, e.g. by Petersen et al., or Baumann et al.
W
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In a paper published this week in nature, researchers at XENON1T reported that they had observed radioactive decay of xenon 124. Xenon 124 went to tellurium 124, and the atomic number went from 54 to 52.
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It's great out of box system experimentation observations!!!!!
Often proof getting hidden in unexpected natural phenomena.....
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Some previous conversions are not practical. For example, when converting radioactive decay model. The fuzzy solutions become negative which is not practical to represent number of particles.
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Excellent answers
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Hi all,
I am currently searching for an antibody against phosphorylated ABCA1 for western blot. I have a Novus anti-ABCA1 antibody (NB400-105) that is working quite well, but cant seem to find a good one for the phosphorylated protein.
I found a couple online (http://www.emdmillipore.com/US/en/product/Anti-phospho-ABCA1-%28Ser2054%29%2C-clone-EPR2485%2C-Rabbit-Monoclonal-Antibody,MM_NF-MABS734 and http://biossusa.com/store/bs-12956r-hrp.html), but cant find any papers that used them, so Im not sure if they're any good. And all papers I've seen that looked at phospho-ABCA1 used either 32-P or ABCA1 IP and then phospho-serine to determine levels of phospho-ABCA1. We cant use radioactive labeling in our lab, so I may try the IP protocol, but would prefer to just find an antibody against p-ABCA1.
If anyone knows of a good antibody for this, or a paper that used one, please let me know!
Thank you so much for your help!
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I would also propose Anti-ABCA1 (phospho S2054) antibody (ab125064) or
(ab248108) from Abcam
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The analysis was done in 50% efficient HPGe 
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dose this rule apply to all radionuclides.
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Hi!
I´m trying to set up a protocol for the evaluation of the internalization of a radiolabelled antibody; all the protocols that I´ve found suggest to lysate the cells and then to measure the internalized fraction of an antibody.
Is this a fundamental step? Or it´s just possible to wash the cells, collect them and measure the radioactivity with the gamma-counter?
Thank you!
Cheers
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Hi Stefania,
We incubate cells at 37°C with radiolabeled antibody and at each time point separate supernatant, cell-bound fraction and cells (internalized fraction) for gamma-counting.
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Spherical symmetry doesn't permit the field configuration different from radial one. From the other side the circulation theorem implies tangent  field with non zero rotor. The solution of Maxwell equation gives loss of symmetry and a hole in the sphere for ' charge supplying wire'.  What's the matter?
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Thnx, Nikolay. I didn't think about this factor at all implying thin wire supplying charge to the ball. But this wire changes completely situation.
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I am assuming decomposition is far more complex than simple decay (radioactive isotope). Because decomposition includes physical, chemical and all other processes.
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as far as I have read, it actually has never been precisely defined. Semantically, decay implies some order of chemistry kinetics, decomposition has much broader meaning, involving both biotic and abiotic processes.
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If radioactivity is rapidly measured after collection in whole blood containaing clot activator (for serum), are there any analytical interference on beta counting measurements?
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First it was beta counting, now it is gamma. Which? If LSC, you cannot use whole blood without digestion.
Will a clot activator be added to heparinized whole blood? Sounds contradictory.
An organic clot activator will not be a problem for gamma.
Please provide a figure depicting the system geometry. Are you using a solid scintillator or liquid scintillation?
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Decay schemes
radioactive materials
radionuclides
software
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Raddecay software.
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I want to perform some radio labeled transfer assays using Carbon 14 labeled amino acids. I know some sources e.g., PerkinElmer, Moravek for radioactive chemicals. If you know any other please let me know.
Thanks in advance!
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Sigma- Aldrich
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Hi
I want to assess radioactive substances inside the plants and wondering which institution/s has/have liquid scintillation counter or isotope assessing facility in Australia.
Thanks
Subhashini
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Hi Steven
Thank you for the message. Will send message to you.
Cheers
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Hi,
I am trying to calculate radioactivity of organs after injecting radio-tracer into body by knowing injected radio-tracer activity and absorbed dose per unit activity. How can I calculate organ's radio activity.
For example : The injected radio activity of radio tracer that injected into human body is 80 MBq and absorbed dose of liver per unit administered(mGy/MBq) is 1.1E-03. How much will be the radio activity of of liver after injecting this radio-tracer? If it is time dependent, could you please explain by considering any time?
Thanks in advance,
Manu
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Absorbed Dose Calculation The amount of absorbed dose (D) is equal to the average energy E absorbed by the body mass of the body or organ mass.
Unit mass (dm = ρ · dV, ρ density, dV unit volume element).
E= of radiation source average energy
D=dE/dm Absorbed dose (gray)
1 Gy = 1 J·kg-1 Then you can convert the absorbed dose to the unit rad (radiation absorbed dose). 1 rad = 0.01 Gy 1 Gy = 100 rad
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  1. attenuation
  2. radioactive sources
  3. thickness need
  4. dose 
  5. risk assessment
  6. build up factor
  7. effective atomic number
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there are many and you can use the equations or some standard curves for every shielding material for software GEANT , Gorbit can be used
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Age determination of unknown human bodies is important in the setting of a crime investigation or a mass disaster because the age at death, birth date, and year of death as well as gender can guide investigators to the correct identity among a large number of possible matches.
Do you think that this time can be extracted using the ratio of decay of radioactive carbon that turns nitrogen after death?
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Rodents will receive calcium injection to specify preferred tissue distribution after my drug treatment. Measuring radioactivity from blood sample is fairly easy, is it feasible to determine tissue calcium de novo distribution from organs? Maybe tissue homogenisation followed by scintillation counting?
Thanks!
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I apologize that the publication I provided a reference for was edited by MMS to preclude the Liquid Scintillation methodology because it was not an EPA approved one. I still have some of my earlier drafts that include the Liquid Scintillation methodology for determining radium-226 in methanotrophic mussel digestate. I will locate them if you are interested in that specific methodology. The EPA approved methodologies are summarized in this publication:
"Fate and Effects of Barium and Radium-Rich Fluid Emissions from Hydrocarbon Seeps on the Benthic Habitats of the Gulf of Mexico Offshore Louisiana". This publication is available at no charge on the internet. The authors are Paul Aharon, Dan Van Gent (myeself) Baoshun Fu, and L. Max Scott. The publication date is 2001. Paul Aharon recently retired from the University of Alabama. Please feel free to contact me at my home page here on Research Gate.
Sincerely,
Daniel Van Gent, M.S., MHP
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I'm speaking of this kind of magic that made radioactivity principles to be discovered. Untidy Becquerel, after an hard day of research, forgot 2 pieces of granite stone on a photographic plaque: that's how he got the first shot of radioactivity. Something he did not planned gave him the keys to understand radioactivity. Because he took the time to recognize his error, analyzed it and begun to plan a theory. At times, life is more generous even and at my humble level, I was so surprised to have shot an image, almost by chance, (because I thought it would be a nice tattoo) and without knowing what it meant, to get aware it was one of the central motifs of my historical-literary investigation: the logo of the famous Manutius family from Venice, who invented book edition: a dolphin rolled up on an anchor. Personally, it gave me the sensation to have entered by chance in Ali Baba's cavern (see my text Antonio Manutius aka Hassan Pacha Veneziano's library). Do you have personal episodes of magical incidents in your research? (Profitable errors, unpredictable things happening, unusual events that change the direction of the wind, etc.)
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Hi, Fred. What I occasionally tell people is, in clinical research, we're all walking through the same woods, and we all trip over the same logs in the woods. The innovators are the ones who look back and say, "hey, that was a log I tripped over!" Everyone else just gets up and keeps walking. The moment with me that comes to mind immediately was diagnosing suppression in vision after whiplash. I think I'm still the only one who has documented the genesis of (intermittent central) suppression where none had been previously diagnosed. I test everyone the same. I had seen a 50+ y.o. man for a routine eye exam and prescribed glasses. He was back 18 months later after a car accident mainly because his glasses got broken. I did the same testing and during the checks in binocularity I routinely do when I had the polarized acuity letters in front of him, he surprised me by saying "hey, this didn't happen before." Then he described his suppression very precisely. I hadn't even asked about suppression, and had no frame of reference to expect a suppression to develop, but since I test everyone the same including those checks of binocular vision, and since he had been in recently enough to remember the last testing, I was able see a suppression where none had existed before - the genesis of a suppression as a function of whiplash. Any time I think I may know something, I remind myself that I learned a bunch from a truck driver who spoke up. But then I got to figure out how that worked. There's the fun!
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Dear all
Can you suggest any method for the detection of RNA binding site in the protein without using radioactive substances.
Thanks in advance.
Cheers
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Hello, Bharti Singal,
you can easily predict RNA binding residues in your protein of interest using this user-friendly web server as an alternative (additional) method to wet lab experiments. For wet lab experiments I would recommend NMR or X-ray crystallography.
Martin
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If I have a package with overalls (Anti c) contaminated with material radioactive inside. This come to contaminated area used by personnel in order to protect of radioactive contamination.
we take a smear the overall and send to the count room, in order to get the Isotopic, but I know that can to calculate with direct radiation, is true?
And we need to transport to the laundry.
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Direct radiation cannot be calculated from the smear. You should measure the direct radiation level with an appropriate dose rate instrument.
It is possible to estimate the total activity and concentration from the radiation rate if you know the package size and the isotope.
More information needed.
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Hi everyone.
I exposed some brain sections, which were treated with 3H-DAMGO, on an autoradiographic film, and as usual in this case, the exposure time was about 1 week.
Unfortunately, at the end I couldn't scan the films so I am wondering if I can expose the same slides to another film.
Tritium has a very low radioactivity but it should be pretty stable (I think, according to the half-life) so maybe after 1 week there is still going to be enough radioactivity so that I can expose the slides again, maybe for a longer time.
What do you think?
Thank you in advance.
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Thank you a lot for the answer!
Yes, I thought that tritium was sufficiently stable but I wasn't sure.
I exposed the slides again and within a week I will see.
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Has anybody some experience doing this kind of experiments? We are trying to quantify glutamate uptake by human astrocytes using the method followed by Pines and Kanner in 1990, with tritiated glutamate.
We have some doubts regarding the methods used to quantify radiation. Is it better to use a scintillation counter or a microbeta? Does someone have a specific protocol to do so?
Thank you in advance!
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Hi! I think that use a scintillator counter would be better. H.
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I want to randomize particle gun within the volume of body phantom. what should be the code for PrimaryGeneratorAction.cc....
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An easy, but very flexible, way to define a particle source in Geant4 is to use the General Particle Source (GPS). You will have to define it in PrimaryGeneratorAction.cc and after that you can use a macro file for inputting your options.
In particular you would probably find useful the '/gps/pos/type Volume' and '/gps/pos/shape Cylinder' command. If you have a more arbitrary volume you can also use the '/gps/pos/confine Physical_Volume_Name' command.
For further details you can always see the section in Geant4's manual:
Also you can find some additional examples here:
I think you could find the examples 10,11, and 17 useful.
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